I have the exact same problem as you, HORRIBLE stretch marks on my underarms and on the sides of my stomach, they are like 1-2 inches wide and 3-5 inches long bright red, and if I push on them it feel like the skin will tear open because it is so thin. Ive lost and gained the same 45-50lbs about 3 times within about a 5 month time frame. Im not sure if that cause the stretch marks, or if they prednisone itself caused them. But I have since been off Prednisone around a month now, and I continue to gain weight even tho I'm eat much less then I was when I was on it. Im really not sure what to do about them, or whats causing them but I have been much heavier then I am currently and before I even started prednisone and never had stretch marks like these. I also had the horrible mood swings, I lost a lot of friends over it, and I guess I cant even say they werent good friends, I was just terrible to them and my family while I was on pred. I would cry randomly, and over nothing at all. Just hang in there, everything will be fine, you wont be on prednisone forever. =)
Dianogsed with Crohns: At 16 years old. 22 years old now.
Surgeries:2 Bowel Resections, Gallbladder Removed.
Current Meds: Humira (bi-weekly), 5mg Pred (tapering), Nexium, B12 injections.