Stop touching the fish or trying to push his jaw into place, you are only stressing it out even more! Did I read correctly you only waited one month after set up before adding fish to the tank? If so that is likely contributing to your issue. The tank is not mature enough and you have some water quality issues causing stress. The gill thing could be a bacterial infection. Less is more. Get back to the basics, 10% weekly water changes, no major changes and leave him alone. Don't overfeed. You say hes eating, thats good. Check alk, ph, and be sure those are stable and in the proper range.