Have Sunburn On Face, Neck, Forearm. Taking Phentermine, Nortrel, Metformin. Reason For Weight Loss, Skin Darkening?

Question: My skin feels like I have a light sunburn. I felt this way a while ago (2 weeks, maybe a little longer) as well, but that day I had been in the sun. Today I feel burned in all the same places (face, decolette, back of neck/upper back and forearms) but only my cheeks are redder than usual, and not like a sunburn, just flushed. My skin also feels irritated/dry but to a lesser degree in other areas that haven't been exposed at all lately such as my upper arms. My lips have been having trouble as well. A few days ago they were burning around the edges then the next day they were all dry and rough, then the next day they peeled off leaving tender soft skin behind then they started with the burning feeling around the edges again and getting a bit rough. They've been much darker red than usual. I haven't used any new cosmetics lately, I hardly use anything on my skin at all in general. I'm on no new medications, although I recently started on phentermine again and it is a tablet instead of a capsule, but at a lower dose. I think it started a week ago, I increased my spironolactone from 25 mg to 50 mg as well at the same time. Other medications I am on are bupropion 150 mg bid, folic acid 800 mg, metformin 500 mg qd, and nortrel 1/35 mg. I list the medications because they are the only changes I recognise besides the weather. I've also lost about 30 lbs mostly over the past 3 months.