I had a wrong stamp ounce at airport and officer in Chiang Rai took care of it and sent a paper to Bangkok and a few days later i had to come back to Chiang Rai immigration office and they corrected it, was very lucky.
not reenter on visa exemption but go to another country and get a 3 months o visa then reenter and after a month and half or 2 get a one year extension in the immigration office where you live