What to do if i have a random burn blister, but i did not burn myself, what could it be?

There are: Certain skin diseases that have blistering as a symptom, without any burn happening. Best to see a dermatologist for an evaluation.

Blisters: Blisters may be caused by disease conditions, injuries or contact dermatitis such as poison ivy. If blisters on the foot are painful and interfere with walking, they may be punctured and drained, using sterile technique. Cause include: fungus, diabetes, bacteria, other infections, bullous diseases, friction and pressure.