I have the same and I now manage to do sit ups. But check with your dr because mine was straight forward. Drinking plenty of water may help but I don't believe you can get rid of it completely. Check your diet also, some foods make it worse. As for your arms, hold your hands out shoulder height and twist arms back and forth. Also, hold arms above your head, bend elbows placing your hands behind your neck holding dumbells or a can of beans and lift the arms up and down from the base of you neck to just above your head. Don't drop the dumbbell - it hurts.
For cellulite - Butt lift is best exercise
For stomach - Running +stretching exercises are good..