Having dental work done can be an extremely stressful experience. I’ve had some done in the past post fin and it takes at least a month, at least, to get back to the prior baseline. So yes, it can be a cause for fin damaged bodies.
On propecia i stopped working out due to fatigue. After I went off propecia and recovered for many months I had some success slowly through exercise over a long period however the success plateaued and then diminished completely. Some people have had more luck. If you try the exercise route don’t overdue it. Start slowly and do not get fatigued as it has been correlated on this site with crashes.