Hi.
Welcome to Practo.
First of all, you need to stop panicking. What white tissue you're describing hasn't happened overnight. It's happened over a period of time.
It's a result of chronic factors.
As your dentist explained to you it's because of malalignment of teeth when they come in contact with each other. For that, if there are sharp edges of the teeth..those need to be rounded off (should be done by your dentist)..so that they don't come in contact with your cheek and cause more trauma.
Second you need to mindfully not bite your cheek..modify your chewing habits if your cheek keeps getting bitten.
And most importantly, like the patches came over time..they will disappear over time or may just become milder in appearance.
You need to believe in the process of your body healing and let the multivitamins work.
You are already in a better place as you don't have any habits.
Next Steps
Continue the multivitamins.
Continue to apply the gel.
Stop overthinking about cancer.