Root Boy Slim is back in town, and for the next two weeks the local music scene will be make better for it.

Returning in triumph from Criterion Studios in Miami where he, the Rootettes and its Sex Change Band recorded their first album for Warner Brothers. Slim held court last week at parties around town and [WORD ILLEGIBLE] , "Tell the other bands to step aside, because Root Boy Slim has hit his stride."

His band combines rich Southern boogie with tacky and outrageous middle-class [WORD ILLEGIBLE] ; add a bit of raunch and his songs become a running commentary on the taste good and bad) of our times - the heartbreak of psoriasis, the gloom of jail in Jacksonville, the December-May romance. "You're 17 and I'm 32, but I'm not too old for you") and his classic "You Broke My Mood Ring."

Witty, urbane but slightly profane, Slim - a.k.a. Foster MacKenzie VIII - promises to draw a remarkable audience: Last summer a 40-year-old Army wife and her 14-year-old daughter were both captivated by his lyrics, most of which are not fit for a family newspaper. They'll be playing eight nights at clubs all over town trying to entice some big money from a management company and working on new material for a winter tour.

But so we don't forget him when he's "gone and famous," Root Boy has promised his hometown fans some special performances - a Christmas show with Slim as Santa and a "pre-Pearl Harbor military show of strength" night Dec. 6. He urged as many women as possible to wear leis and grass skirts. WHERE AND WHEN

Root Boy Slim and the Sex Change Band: Friday, back room of the Varsity Grill, College Park: Saturday, Fairfax Theater (with Frannie Day and the Manports); Sunday, the Cellar Door: Monday, Desperados; Tuesday and Wednesday, the Childe Harold; Friday, the Psyche Delly; and Saturday, the Grand Ballroom, University of Maryland, College Park.