I get them on the outside of my upper arms. There is no head or oil or "zit" like appearance to these bumps. They feel dry & I usually scratch off the "dry skin bump" ( they are not in patches or even next to each other. What is bothering me the most is how long it's taking them to heal. I could see a 2 weeks, but when it's more than a month, then I get concerned. I am not menopausal & have had a partial hystorectomy. They do not re-appear in the same place usually (a couple have twice tho). Nothing around my shoulder or underside of my arm & nothing below the elbow. They just don't appear like pimples or ingrown hairs. ???
I agree with Clara in some regards, try not to scratch them and even put a little circle bandaid on them if need be. When you scratch a scrab of before it is time to fall off the healing process has to start all over again.
It could be acne. I get one or two pimples each month with my period. They're usually on my face, but sometimes they're on my back, my scalp, or my arms. If it is acne, remember that flare-ups are caused by surges in hormones, and any number of things natural (like periods) and womanmade (like obesity) can cause hormonal disturbances.
I'm not sure if you mean the bumps recur in the exact same spot or not. If so, it could be they're recurring there because you're aggravating them by picking.
Regardless, try not to scratch them off and just see what they do--how long they take to heal. My last period pimple has been with me for almost three weeks now (very rare for me), but it's healing so no scab or scar. The antibiotic cream won't do anything unless the wound you created when you picked at it became infected. An acne-fighting topical med that usually works for you might be better because it will help you (and your derm) rule out acne if that's one of the possibilities.
Getting a second opinion is smart. Don't tell the second derm that he/she is the second opinion. This way, if the answer comes back "acne," you'll be more than likely satisfied.