3 1/2 Months After Mole Removal, a Bright Red Bump Remains. Why? (photo)

It is a little difficult to assess by the photo.  I would advise you see your physician for a follow-up appointment.  It may be that it is a hypertrophic scar that may need a cortisone injection. 

You should see a derm surgeon for your red bump. Often it needs only a little cortisone shot to make it disappear.  It has been going on too long to just let it be.  Sincerely,

David Hansen,MD

It is difficult to tell from the picture, but it is possible that you may have developed a hypertrophic scar at the site where the mole was removed.  Hypertrophic scars look raised and pink and are more common in areas where there is a good amount of tension on the wound as it heals. There are treatments to improve these types of scars such as intralesional Kenalog (cortisone) injections. I recommend you consult with a board-certified dermatologist who is experienced in dermatologic surgery. 

It's hard to tell over the internet what is the cause, but sometimes you can develop a thickened or hypertrophic scar after mole removal on the arm. Since you say that the two doctors that you talked to were not too familiar with the problem, you might consider consulting with another dermatologist, one with additional training or experience in skin surgery. There are many excellent dermatologic surgeons or fellowship-trained Mohs surgeons in Los Angeles that can evaluate the problem and help improve or resolve it. If it is a hypertrophic scar, they might consider intralesional steroids, pulsed dye laser and/or silicone gel bandages. If it's something else, they should be able to help as well. Good luck.