Can i go to er for infection in the mouth due to tooth abcess?

Yes, but ....: An ER will only prescribe pain medication and antibiotics which will give short term relief - pain and infection will recur unless you see a dentist who will actually treat the cause of the infection.

Check first: Call the ER to see if they have Dentist/Oral Surgeon on staff. Physicians are not trained or experienced at treating Dental Infections. But you need Rx NOW. See Dentist ASAP.