Hey Chris,
I don't want to alarm you but please def get it checked out! The dentist would be the best place to start. I had a blister, well started as a blister!! Ended up being mouth cancer. Be persistent too, it took me 3 attempts before my dentist finally sent me for a biopsy. Luckily caught in time but I've also had to endure a mandibullectomy. I had brilliant mouth hygiene too, non smoker. For your own peace of mind just get it checked. Hope it all goes well.