My son has had bumps on his arm for years. he's 12 now. he is using cerave lotion now. a little better. will it disappear over time?

Get checked: If he has had this skin change for years, it's not likely to get better right away, until it is diagnosed, found to have a treatable cause and treated with a treatment specific to its cause. Hope that helps.

Bumps on arms: If these bump are are mostly on the upper back of the arms then it is likely Keratosis Pilaris and very common. It's genetic which means that it runs in families. If is not like acne and acne medicine does not help. I recommend keeping it moisturized and periodicly a mild exfoliant. Keratin is a skin component and as the skin renews it's self it gets better. Do not pick at it.

Hyperkeratosis-Mayo: Keratosis pilaris is a common skin condition that causes rough patches and small, acne-like bumps, on the arms, thighs, cheeks and buttocks. Keratosis bumps are usually white, sometimes red, and generally don't hurt or itch. Keratosis can be frustrating because it's difficult to treat. However, it isn't often serious and usually disappears by age 30. In the meantime, prescription medications and self-care measures can improve the appearance of keratosis pilaris.