Keritosis pilaris!

http://www.aocd.org/skin/dermatologic_diseases/keratosis_pilaris.html

Keratosis Pilaris

Keratosis pilaris is a skin condition commonly seen on the upper arms, buttocks and thighs. The skin cells that normally flake off as a fine dust from the skin form plugs in the hair follicles. These appear as small pimples that have a dry ''sandpaper'' feeling. They are usually white but sometimes rather red. They usually don't itch or hurt.

Keratosis pilaris is particularly common in teenagers on the upper arms. It may occur in babies where it tends to be most obvious on the cheeks. It may remain for years but generally gradually disappears usually before age 30. Keratosis pilaris is unsightly but completely harmless. It is usually worse during the winter months or other times of low humidity when skin dries out, and may worsen during pregnancy or after childbirth.
 
Treatment of keratosis pilaris is not necessary, and unfortunately often has disappointing results. With persistence, most people can get very satisfactory improvement. Initial treatment should be intensive moisturizing. Try a cream such as Acid mantle, Vaseline or Complex 15 after bathing, and re-apply the cream again several times daily.

If this does not help, change to a medicated cream containing urea (Carmol, Vanomide, U-Kera, Ultra Mide, Nutraplus) or alpha-hydroxy acids (Aqua Glycolic, Lacticare) applied twice daily - it may be too irritating to use more often. More aggressive home treatment can be done if ones skin can tolerate it. The plugged pores can be removed by taking long, hot soaking tub baths and then rubbing the areas with a coarse washcloth, stiff brush, or 'Buf-Puf'.

Prescription medicines that may help include antibiotics (Erythromycin, Bactrim) if the spots are very red and Tazorac Cream. Tazorac, a relative of vitamin A, may cause irritation in some people.