A team of surgeons has made a new face for a young woman who couldn't bear to look in her mirror, a woman whose face made her own parents turn away.

For nearly nine hours Tuesday, four University of Pennsylvania doctors reshaped the features of the 21-year-old woman, who has been afflicted since birth with a disease called neurofibromatosis--NF.

Better known as "Elephant Man's Disease," for a famed victim in 19th century London, the disorder covered her head and scalp with growths--thick, grayish, hanging and overlapping eruptions and folds, giving it the rough appearance of the skin of an elephant.

"Words fail me to describe how she looked," said a woman who met her.

On Friday, three days after her surgery, that woman said, "My God, she looks 500 percent better. It's incredible."

The young patient, who asks to be identified only as "Lisa H," not her real name, had the severest form of the disease, which in many persons is mild.

The surgery does not cure the disease, and Lisa H still will have thick, grayish skin. But she hopes that now she will be able to go out without being taunted by children.

If the operation's early success holds up permanently, the surgery on Lisa H will be remarkable, even in the often remarkable world of plastic surgery.

Neurofibromatosis is primarily a nerve disease that produces growths that push their way through the normal skin. About half the cases are hereditary. The others apparently are caused by spontaneous mutations or changes in the genes that set off the disorder; no one knows why.

The growths that result actually are nerve cell tumors, called "benign" because they are not cancers. They are anything but benign in their effect, however. In Lisa's case, the disease had progressed to the point where her left eye was all but blind and many facial bones were weakened or destroyed.

Lisa had had 11 operations since childhood. Some, to try to save her now virtually useless and grossly enlarged left eye, failed. Three attempts to remove growths also were unsuccessful; the growths returned. Other operations were recent explorations to help plan last week's surgery.

The chief surgeon in Lisa's operation Tuesday, Dr. Linton Whitaker, knew he would have to be far more radical. He would have to remove more tissue and destroy many facial nerves. He would have to take chances even with Lisa's life, since there would be profuse bleeding.

But he knew, too, that there was a good chance that the disease had stabilized, so the growths, once removed, this time would not reappear.

He knew also that Lisa is a remarkably courageous young woman, by all descriptions. A New York Times reporter described her as "bright, friendly, engaging, optimistic," a realist who said, "I know that I am not going to look like Farrah Fawcett-Majors...I would elect to have this surgery even if it gave me only 1 percent improvement. But I think it will be much more than that."

So did Whitaker. He is one of the nation's leaders in cranio-facial surgery, a territory opened in the late 1960s and '70s by a French surgeon, Paul Tessier. Tessier directed plastic surgeons away from the lower face alone to the eyes and skull, areas they had shunned for fear of damage to the optic and other nerves and the brain.

At 9 a.m. Tuesday, Whitaker and colleagues--three more surgical specialists, assistants, technicians, nurses, an M.D.-anesthesiologist --began.

They cut away many massive growths. They lifted the skin and the scalp to get at the roots of the growths. They sliced away large amounts of abnormal skin to leave a smoother, less lumpy look.

They removed the virtually useless left eye and remade the eyelids, replacing a set that, like so much of Lisa's old face, hung down in folds to her cheeks.

Lisa's nasal bones had been demolished by the disease. The surgeons made new ones, using several of her own ribs to rebuild this and other parts of her face.

Whitaker and colleagues were forced to sever some nerves. Some parts of her face will therefore be permanently insensitive. The surgeons hope she will still be able to blink and wink, and they tried to leave her the ability to work her mouth and be expressive.

The final result of the surgery will not be known for some time.

On Friday, however, the doctors removed the bandages and dressings from Lisa's face. It was very swollen and will be for another week.

But "the doctors are all very pleased," said a hospital spokesman.

And Lisa? "In good spirits, too, and very pleased."

She is aware, of course, that all Whitaker could hope for was a "compromise."

Such is the fate of many of the 100,000 or Americans with this disease.

The disease was little heard of until the story of John Merrick, a London victim who became something of a parlor pet among the fashionable, was told in "The Elephant Man," a 1979 Broadway play and a 1980 film. Merrick, whose whole body was affected, ultimately became a sideshow freak just to eat. The disease affected so much of his body that he could not breathe lying down, and he habitually slept in a chair.

One night, however, whether purposely or not, he did sleep lying down, and suffocated.

Merrick and Lisa H are counted among the most extreme and uncommon victims of neurofibromatosis. Most NF patients have the disease in lesser guise. Some have only patches of discolored or blotchy skin. So far, surgery is the only treatment.

One thing seems encouraging, said Rita Kasky, executive director of the National Neurofibromatosis Foundation in New York. More people are hearing of the disease, and this may at last bring more understanding.