Freezing can cause temporary darkening, especially in people of
colorColor blindness
Color blindness tests
Color vision test. But that wouldn't explain their still being there after 2 years, much less darkening. It doesn't sound like anything serious, but you'll need to see a dermatologist in person to find out for sure. Fade creams aren't very effective on the body (as opposed to the face), and besides, you want to know what something is before treating it.
Best.
Dr. Rockoff