I went to Costa Rica in November for 3 months. Since I've been back I have these bumps on my legs that wont heal. They still itch. I have about thirteen on my left leg, and 5 on my right, They are small bumps with a dark edge around them. I'm starting to freak out becuase I have been back for 5 months now and they still itch, and some have changed in size. Do you have any idea of what this could be?