carpal tunnel surgery side effects

My mom is 66 years old, she has severe bilateral carpal tunnel on both hands. She also has arthritis on her fingers. 2 months ago she had a surgery on the right hand to release the carpal tunnel. Her numbness and tingling is gone. About 1 month after the surgery she has pain on where the stiches were, then it dissappeared. She does physical therapy once a week, and she is very diligent doing it on her own at home.

Now, after 2 months, for the last 3 nights she had the pain again around where the stiches were, and last night it went to her fingers too. She is suppose to have another surgery on the left hand side, but she is worry because she still has pain on the right hand. I am wondering if this pain after 2 month of carpal tunnel surgery is normal. Maybe she overdid the therapy at home ?
Thank you.