Small hard bump on roof of mouth that gets softer and harder as day goes on. have had it for three months, not painful more so annoying. mouth cancer?

Cyst: It could be a mucocele but since you have had it for 3 months, i would recommend that you see your primary care or ENT specialist.

See Your Dentist: It sounds more like a possible abscess or infection than cancer though that cannot be rule out without examining it. If infection, it could be a tooth or your sinuses either of which can explain why it is soft then hard but not painful - it is draining some where which makes it softer then pools overnight. You've waited too long to not get it is taken care of!

Exam: Statistically unlikely but possible. See oral surgeon or ENT doc for assessment.