Can lidocaine hydrochloride be used for a painful swollen rash in the pelvic area regardless of the label saying its for oral use? or is it more likely that i had mistaken what my doctor prescribed it for? (i had an allergic reaction to antibiotics?

Probably won't help: This probably won't help. I hope your rash has been diagnosed. A common cause of "painful swollen" rash is herpes zoster (shingles). Severe genital herpes can be similar. Either one of these should be treated with an anti-herpes drug such as valacyclovir. Check back with your doctor if there is any doubt or uncertainty about the cause. Good luck.