Hello everyone ! My first post here and not very good with english, so bear with me

I had my wisdom tooth on lower jaw surgically removed on 7th April. But after 3 days (on 10th) i had to go to hospital because i had developed an infection (abscess) and they had to drain the puss with incision from the outside of my cheek. I was released after six days (on 16th).
Now, the problem is my jaw is still stiff, the doctors told me i should try to stretch my mouth as much as i can, but still the progress is minimal, i can brush my teeth normally, but still can't eat unless it is in small pieces.
I am starting to wonder, since it's been a week since my release from hospital, how normal it is to still experience stiffness and how long will it take for my jaw to return to normal state?