What Causes Purple Wrinkled Skin On Thigh And History Of Having Thrombophlebitis?

I had thrombophlebitis at the beginning of the year and am being treated with warfarin - measuremnt on blood count now 2. I have developed purple wrinkled skin at the top of the thigh on the same leg. No itching or pain. BUT is it serious? Also my thighs and back are very painful when walking and this has been so for a couple of years.Thanks