She had worked all night at Oneita Mills, stitching shirts for $4.50 an hour to feed an unemployed husband and two children, and as she walked into the rain-soaked dawn with 500 others on the graveyard shift, Karen Lane felt someone shake her calloused hand.

"I need your help," said Rep. John L. Napier, an embattled Republican freshman who asked yawning mill workers to send him back to Washington.

Karen Lane, a blue-collar Democrat, said she just might, even though she blames President Reagan for her predicament and Napier has been a good soldier for Reagan in Congress.

"It just don't seem like Reagan's policies are fair," she said, pausing in the parking lot. "My husband works so hard and he can't find nothing."

"I heard about him Napier on TV," she said. "He may be a Republican, but I'm not prejudiced. He doesn't have to be like Reagan. He might be fairer to us working folks. Anything's better than Reagan."

To survive, the family had to move in with her uncle. Even though she is working now, she fears layoffs that have ravaged textile, steel and paper mills in Napier's district, where unemployment is two points above the 10 percent national figure.

Napier is in a fight for survival in a close race against Democratic state legislator Robin Tallon, 35, a self-made millionaire haberdasher who is running against Reaganomics.

Napier's reelection largely depends on whether independents and Democrats like Lane distinguish him from Reagan.

Napier bolted on Social Security cuts and voted against the president's tax bill because struggling farmers here feared that new cigarette taxes would cut into sales of their only profitable cash crop: tobacco. Most of South Carolina's flue-cured leaf is raised in this district. The bill passed, but Napier was credited for trying.

A former staffer for Sen. Strom Thurmond (R-S.C.), Napier lives by a beatitude practiced by his political godfather: stay independent from thy party leaders. He rarely mentions the president on the stump; literature is devoid of party label. Only when pressed does he defend the Reagan economic program.

"He's a Republican, but above all he's his own man and that's the kind of campaign he's running," said Lee Atwater, deputy White House political affairs director who has advised southern Republicans for more than a decade. "His whole image is that of an independent type guy, and our polls show the voters know that."

So, Napier has been touting grants to Myrtle Beach Air Force Base, taking some credit for saving jobs as a result of International Paper Co.'s $500 million factory modernization in Georgetown and stressing his ability to get things done in a Republican world.

"Any congressman should have done that," countered Tallon. "He talks about supporting legislation, but he never gets anything passed. He's tied to an administration that's determined to destroy the small farmer."

Tallon trails in name recognition (92 percent know Napier) and money ($300,000 projected to Napier's $400,000) in seeking a seat Napier barely won by 5,000 votes from Rep. John Jenrette, the popular Democrat who was convicted on Abscam charges. Napier is fighting the district's Democratic history and the image of a fluke.

Tallon counts on the black support--41 percent of the district is black--that nearly saved Jenrette and who are less likely than whites to separate Napier from Reagan.

He has inherited Jenrette's organization. Black preachers are said to be reminding voters that Napier, who got only 3 percent of the black vote in 1980, voted for a watered-down version of the Voting Rights Act before he backed the stronger bill that passed.

"I don't know if Jenrette's enthusiasm will transfer, but the economy will certainly push blacks to Tallon," says Dr. R.N. Beck, 59, a respected family practitioner who heads the district's black caucus. "Black people don't separate Napier from Reagan."