Thank you. Neither of my siblings have it and I'm not aware of any other family members.

I also think it is panniculitis (inflammation and then atrophy of the subcutaneous tissue). This happens in lupus and mixed connective tissue disease. Your MCTD diagnosis previously is because of the positive ANA with RNP antibodies. You have Raynauds and finger swelling, both classic in MCTD. Raynauds can be white, red, blue or purple. Of more concern are the stroke and TIA. Over 30% of people with lupus ( part of MCTD) have anti phospholipid syndrome, which can cause clots that cause heart attacks, strokes, DVTs, blood clots in lungs, eyes etc. A simple blood test can tell you if you have that. (Anticardiolipiin antibodies). If so, you need to be on medication to prevent clots! Please see your Dr and get that test done and see a rheumatologist for the MCTD. A dermatologist can do a biopsy of the dent with immunoflourescent studies to nail down the panniculitis diagnosis. The immunoflourescent study on the biopsy tissue is essential. The dermatologist can also inject a steroid to help halt the inflammation and progression of the dent. Then later a “filler” can be injected to improve the appearance. Those have to be repeated periodically. I know this is a lot to digest. Do some research and look at images online of panniculitis. Lipoatrophy follows the inflammation. I hope you get help and future problems prevented! Take care.