After getting these blisters on and off over the last few years I also googled the phenomenon.
I also get blood blisters from biting the inside of my cheek when eating food/s, even when being really careful! Sometimes I go for months without getting them, and other times I have had two in one day!
I do avoid sharp foods as a result**, potato chips are the worst culprits, as are crusty breads and also pizza bases. I've never had them from hot drinks.
Another factor I can relate to is stress. I have a pretty stressful lifestyle, unfortunately, which I am working on making into a less-stressful one, but that's a long term goal. The blisters do seem to coincide with when the stress was diagnosed! (so could be a blood pressure thing too) idk?
I also eat very well (I have trained to be a personal trainer/diet coach), I don't and never have smoked, and I drink on occasion.
Either way, as suggested several times here, I just leave them be. I used to burst them but sometimes, which resulted in more pain lasting several days. I know how annoying and a little scary they can be, especially when they just pop out-out of nowhere! But, they ALWAYS go within 48 hours, or less. I've had them swell and go back down in less than 10 minutes, and I have also watched them swell in the mirror (which is not very pleasant, but from a medical aspect its probably very interesting!).
I also suffered with mucoceles for many years (fluid filled blisters on the bottom lip and cheek lining), my last serious one was about 2 years ago. After many doctors/hospital visits (resulting in several surgeries), ...and reading on the internet it's pretty obvious that these too are caused by trauma/s to the mouth lining.
**As a nurse once said to me, 'prevention is better than cure'! I couldn't agree more! I have since changed the way I sleep, which has removed the white lines on the insides of my cheeks, where my teeth were rubbing whilst sleeping, and when eating I am very conscious about how I chew (although the odd mishap can occur)(maybe as I said this is stress related, worrying about getting the blisters whilst eating, lol, a true vicious circle if ever there was!