this might be a form of a genetic condition called keratosis pilaris. it can also occur on the upper outer arms. some people grow into it over time others are lucky and grow out of it over time. you can control it but not cure it. products containing lactic acid salicylic acid and glycolic acid alone or in combination can be very helpful.
i have small red bumps on my inner thigh and part of my butt. cortisone cream and benzoyl peroxide didn't work. help!