Hi
The white blisters in your case could be canker sores that appear for no particular reason. They can be due to Vitamin B12 deficiency, mechanical irritation, a virus or due to a decrease in temporary decrease in body immunity. They could also be moth sores caused by hot and spicy food.
Most sores of either variety will disappear in 10-14 days. Some may persist. There are some remedies for both: Gargle with cool water, avoid hot beverages and foods, spicy and salty foods, take pain relievers like acetaminophen or take a multivitamin tablet.
However it is difficult to diagnose without examining. So please consult your doctor. Hope this helps. Please let me know if there is any thing else.
do you have any on your fingers or toes. if o it could be fifth's diease (foot and mouth) not sure what else it could be but I hope they go away quickly so you won't be sore
michelle