It is a good idea to get yourself a legitimate driver’s license if you are going to be driving a motorcycle, scooter or car.
The obvious benefit is that you will be fully legal to drive in Thailand. If you get in an accident without having a proper license you could end up paying a lot more money or worse if it is a serious accident. Plus now the traffic police will have no reason to ask you for a money unless it is for some other reason like not wearing a helmet.

Following is quite a good article on how to go about this in Chang Mai although the same steps can be followed else wear in the country.

How To Get A Thai Drivers License