Should I see a specialist for ulcerative colitis, or can my regular doctor take care of it?

Depends. Ulcerative colitis comes with different severity. If your family doctor is comfortable with your progress and you are minimally affected, that can work out. But if you have daily symptoms and need for going to the bathroom, or lots of blood in your stool, or you feel sick all the time, you may need a referral to a GI specialist with special training in treatment of uc.
Need specialist. Ulcerative colitis requires close monitoring by a gastroenterologist. Not only is this a dynamic disease where treatment strategies are constantly changing, but risk of colorectal cancer is increased requiring surveillance colonoscopies. Patients may do well while in remission and feel a specialist is not needed. However, the disease is unpredictable and can flare at any time.