There are many different causes of lumps and bumps on the skin so it is very important to make an appointment with your primary care doctor
to have a full history and physical to determine the correct diagnosis and treatment for your condition. One of the most likely causes is a condition called keratosis pilaris, or KP for short. This is a benign condition that tends to run in families. KP usually presents as small bumps that can feel rough when touched usually on the upper outer arms and on the thighs. Another possibility is razor burn if you recently shaved this area. It is also possible that you are having an allergic reaction to something new that this area was exposed to. Some sexually transmitted diseases do not show up right after sex so even though you aren't currently sexually active, if you ever were in the past you want to get this checked out to make sure it is not an STD
. Please make an appointment with your primary care doctor as soon as possible to have this rash examined so that you can obtain a correct diagnosis and get appropriate treatment if it is needed.