I have been getting pimple-like bumps on my arm. they do not itch or hurt most of the time. the end up popping like pimples, scabbing and scarring.?

Folliculitis: The condition is possibly inflammation of hair follicles which can result in bumps, crusting etc. Rarely some areas may progress to micro abscess formation. Topical Bactroban (mupirocin) Cream offers relief and helps with the healing process.

Maybe KP?: This sounds like a condition called keratosis pilaris. It is essentially due to trapped hair follicles with small ingrown hairs although the exact cause is not truly known. A wide variety of options ranging from chemical to mechanical exfoliation, urea treatments, retinoids and even laser hair removal have been used to mention a few interventions. Avoid picking/popping which leads to hyperpigmenta.