Thanks for posting your query
The itchy red rectangular rash
could have been a skin lesion and not related to surgery
I would suggest you see a good dermatologist
and in the mean time take a dose of Tab Cetrizine
daily to control itching
What was the type of surgery performed Open or Laparoscopic ?
Where exactly is the swelling occuring in upper abdomen ?
There are probabilities you have post cholecystecomy syndrome ?
Avoid fatty meals
Take small frequent meals
And for medications consult your health care provider
Hope this helps
Am available for any followup queries
If there are no further doubts, do accept this reply and rate it
Get Well Soon