Well that's quiet a common problem. If the clots as you say are just palpable, not visible. Then it seems to be a benign problem mostly due to rapid growth (horizontally/vertically, this represents nothing but torn ends of the fatty layer (adipose layer) of your skin. Do not worry about it. It takes years together to get subsided.

Hi, it could be Lipoma. A lipoma is a slow-growing, fatty lump that's most often situated between your skin and the underlying muscle layer. A lipoma, which feels doughy and usually isn't tender, moves readily with slight finger pressure. Lipomas are usually detected in middle age. Some people have more than one lipoma. A lipoma isn't cancer and usually is harmless. Treatment generally isn't necessary, but if the lipoma bothers you, is painful or is growing, you may want to have it removed.