Hi, Welcome to Health care magic forum.
As you describe, it appears to be the
surgical hernia, with the intestines or omentum comes out of the internal sutures, and stay under the skin.
If it is hernia it recedes when lying on the back.
If it is not hernia you must try strenuously for reduction.
Avoid taking calories, fats, junk foods, and oily foods,fleshy fruits like banana, and guava.
Have morning walk,
yoga, gardening etc.
Minimise the sleeping time, late to bed, and early to rise.
Wishing for a quick and complete recovery. Thank you.