Pain in inner thigh?

Had pain in inner thigh after a excerise...3rd day the area became reddish ... pains only in the reddish area,not at other areas.Started Metformain 1 week before.Somehow i feel i had put on weight on my thighs.Is it ok? or anything bad.Herpes?bad skin rash?food allergy?I am 30 yr old woman,using my husband ID.|||Could be a bruise from the muscle strain. Take it easy for a few days and see if it goes away. If it doesn't, please see your doctor.|||could be number of things not enough info to even guess email to discuss further if you wish!