What can i do for an abscess on hard palate?

See your dentist: Depending on the source of the abscess, treatment will vary. Being in the palate makes it close to the eyes and the brain. You should take this seriously.

Need to be seen: An active infection can effect the entire body. It will no go away on its own. I would recommend you see an oral surgeon asap as they deal more with pathology than general dentists. It may not be an abscess?

Have evaluation: See your dentist to determine whether or not it's an abscess, and if so what's causing it as well as what your treatment options are.