What to do if i have an under bite, how severe is it?

Hard to tell...: ... unless you are examined. A local orthodontist, during your consultation visit, will explain how severe your malocclusion is.

Significant: Underbite usually means jaw size disproportionality. Think what it would be like if you had one leg a few inches shorter that the other, and what that would do to your knees, hips, spine, gait, etc., over time. Please see a qualified Orthodontic Specialist who can discuss the extent of your problem and the available treatment modalities that relate to your malocclusion.

Seek consult: "Underbites" come in many varieties. Some are related to tooth position and others are related to boney or skeletal discrepancies. A well trained orthodontist can differentiate these and provide treatment to correct the problem. Early correction helps prevent resultant tooth damage to front teeth.

See Orthodontist: Most orthodontists do free initial consultation, that should help you to determine treatment options if to do you have an under bite. Regardless, what may be the reason for your concern, you need to consult orthodontist.