I have a very small brown dot on my tongue... it is extremely painful but only if i accidentally run my teeth across it. it is a very sharp pain.

Duration ?: How long has this brown dot been there? If more than two weeks, have an oral surgeon examine it.

See DDS or PCP: Brown dot on the tongue that are accompanied by other symptoms such as pain or difficulty swallowing should be checked by your dentist or doctor as soon as possible.

Can't see it: Can't examine you over the computer, but any pain/bleeding/swelling should be evaluated. Ask your Dentist to recommend an Oral Surgeon, a specialist in diagnosing and treating oral lesions.