Need advice on whether or not I need medical help to improve my bite (Photo)

Overbite of 4-6mm chin 2.5cm away from lip, aching joints, uncomfy bite, headaches, have to move jaw forward and backward uncomfortably when eating, not to mention profile is pretty ugly and isn't helped by large build up of fat around jaw even when skinny, recently talked to my dentist about these problems who said she could give me a mouth guard at night to help and I look normal, I don't believe this will solve my problem, should I seek second opinion privately or just deal with the problems?

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