Mysterious Roof of Mouth Rash

[Lpyper33]

I am a 28 year old female with no known allergies. Last year, the roof of my mouth began to get very itchy and it was very rough and bumpy on both sides of my hard palate and soft palate and a little swollen. It's stuck around for two weeks and got worse anytime I would eat or drink anything. It was very annoying. I have had it reoccur three times since then and sticks around for about a week. I pay attention to what I'm eating before it happens and it's nothing I don't normally eat on a daily basis, so I'm having a hard time thinking it's a food allergy. It flared up again yesterday and it gradually gets itchier especially when I eat or drink for about a week and then it seems to shed the skin and become smooth again. Anyone have any insight to what this could be? I keep thinking it's an oral allergy, but it lasts for a week. I suffer from cold sores on my lips but it doesn't seem to look like that.