Blisters in the mouth can be caused by a variety of factors, including infections, injuries, and underlying health conditions. Here are some of the most common causes of mouth blisters:

• Herpes simplex virus (HSV) infections: This virus causes recurring episodes of small, painful, fluid-filled blisters on the skin, mouth, lips, eyes, or genitals. Cold sores of the lip and ulcers on the palate are perhaps the most well-known.

• Canker sores: These are the most common type of mouth ulcers. Healthcare providers aren’t exactly sure what causes them or why some people get them more than others do. Causes include minor trauma (like biting your cheek), acidic foods, and even stress. Canker sores are usually white or yellow with red around the edges.

• Gingivostomatitis: This condition may be caused by a bacterial or viral infection, or it may be linked to poor oral hygiene. Gingivostomatitis is characterized by cold sores in the mouth — usually on the gums or inner cheeks. It’s most common in children.

• Oral thrush: An overgrowth of yeast called Candida albicans causes this fungal infection inside your mouth. It commonly happens after antibiotic treatment or when your immune system isn’t as strong as it usually is. Oral thrush causes red and creamy white mouth sores and patches.

• Injury: Accidentally biting the inside of your cheek, injury from a toothbrush, constant rubbing against misaligned or sharp/broken teeth, constant rubbing against dentures or braces, and burns from eating hot food can all cause blisters or ulcers to form in the mouth.

• Autoimmune diseases: Certain health conditions, including many autoimmune diseases, can also cause mouth ulcers.

Its important to note that mouth ulcers are usually harmless and most clear up by themselves within a week or two. However, if you have a mouth sore that doesnt go away, unexplained numbness in the face, mouth, or neck, or problems chewing, speaking, or swallowing, you should see a healthcare provider as these could be symptoms of oral cancer.