When Can One Start with Sit- Ups After Panniculectomy and MR?

I had panniculectomy and muscle repair on sept 26 about 2 wks ago I started with sit ups and core excersises and I am in alot of discomfort and my stomach seems to feel hard and swollen, is there a possibility I hurt something, I get very sharp pains too when I am not doing anything through-out my stomach for no apparent reason still it has only been 4 months and I have alot of big large balls underneath the scar line that hurt if I lay incorrectly. am I just healing still