Hello and welcome to the forum! Sorry for your concerns and we hope the biopsy brings good news. I strongly suspect it will. There are different reasons for why you could have this bump on the roof of your mouth. https://www.healthline.com/health/bump-on-roof-of-mouth#hyperdontia Oral cancer is just one possibility and given your age and lifestyle choices, it really is unlikely to be the cause. That it flares up and then goes down is further a sign of this. But it is wise to have it checked. It sounds to be more along the lines of a cyst but your biopsy will give the final answer. Please come back and let us know!
So glad to hear the biopsy did not show cancer. I'm sure you are breathing a sigh of relief. Congratulations. We have an Ear Nose and Throat forum if you want to post there as well. Find it under communities. But again, great news!