Have sensitivity to Pcn and sulfa. PA prescribed clindamycin. Concerned since I've had terrible itch (similar to yeast infection from when I was young) in perineal area since before Christmas- not vaginal opening, but more on labia and anus. Thought it was more of a cyst, itch is releived by Allegra topical. Also culture was negative. Had my "routine" blood work this morning, Should I wait for the lab results before taking this?