While I was there, we didn't use Doctors, we would go to one of the many pharmacies scattered around. There you can pick up all kinds of medicines and treatments. For more serious illness/injury, there are small clinics located in the touristy areas. I would recommend Prime Plus Medical (Canggu/Seminyak region) where a friend had a pretty horrific scootering wound stitched up. In the case where a hospital is required, Siloam usually does the trick. If the injury is very severe and invasive surgery is required, if possible, I would avoid treatment in Indonesia.