Of course your masseter muscles were partially cut and stretched (the attachment lines). The muscles need at least 2 years to adjust.
Pray to not get TMJD
but since you have not got as far it will be OK..especially if you had surgery bilaterally. So there is compensation. Symmetric change
if I remember what kind of surgery you had
The muscle line attachment very likely has attached again properly. However you can check it on MRI, or even on CT you can see kinda echo of soft tissues
If there is really tightness, you can try botox injection into muscles. But do it wisely. Hovewer at this point don't do anything. Too early
I wonder do you see some negative changes when you open your mouth widely ? I mean, the soft tissues between the zygomatic arch and the border of the jaw
How is your feeling ? the nerves