Damo,
You know in nearly three decades I have heard just about everything in post-op conditions. What you are experiencing may be more related to your nerves in the dermis, but it's hard to say. I do know that there is always a variance in patients' post-op experience including regaining laxity. Nerves are severed during the procedure, and they do mend themselves and even regrow to some extent, but again, the time table can vary. IMO, you have nothing to worry about. See your Doctor if it does get any worse in discomfort.
Some patients like Falc regain laxity relatively quickly and others take much longer. I have been through four hair transplants myself and can tell you that I am still as tight 11 months post-op. If I do any touch ups, it will take FUE.
Yes you can do scalp excercises that stretch the scalp, but unless you are in any discomfort, there's really no need to.
Now if you do decided on another procedure sometime in the future, you may very well indeed need to do these or you will be a FUE candidate like myself.