.
This is definitely not something for the internet
If you are in the UK get your GP to refer you to a max fax surgeon and at the first interview all this will be explained
Clearly he will wish to discuss whether your underbite is getting worse and whether it is related to wt lifting.
- or he may not, Try it and see.
jaw clenching during wt lifting - hmm I can see that 6 wks may not be enough.....
time to ask an expert