It will shrink. People tend to have sides including this one when they tank their DHT which was giving them all those benefits. So especially those with low T to begin with are left with nothing.
Penis can shrink due to no erections (no dht and no blood flow), no masturbation (no stretching) and due to faulty circumcision. Why you may ask. Because they cut too much skin and force the penis to either bend with time or just not be able to reach its full length. To correct that through surgery the only way is to cut skin from the testies which is also flexible, after having the area lasered, and attach it to your penis. It’s a very complicated surgery.
To lengthen the penis you can get an extender, do some blood flow routines such as jelqing(?) and stretch your pelvis. Losing fat and lasering those areas automatically add the illusion of size. I haven’t done the latter but planning to do so.
For girth not so much you can do. In the future there will probably be ways through injections. Increasing blood flow is the only way to increase girth but overstretching and this increasing size at the same time reduces girth so pay attention to that unless you want a lengthy pencil as a penis.
For anyone asking I am a 7,5-8 inch fella so I know my sh*t.