Do you have rough, bumpy (usually red) skin on the back of your arms? This is called Keratosis Pilaris or chicken skin. It is very common and harmless but annoying.They are caused by dead skin blocking the hair follicles.
Solution- Use a Chemical and Physical Exfoliant. (see the picture for recommendations). Do this 2-3x a week. You probably won’t be able to get rid of this permanently but if you are consistent, it will improve the skin a lot!