You need to drink more water, keep a light diet and eat more vegetables and fruits to get blisters inside your mouth. You can take medicines to remove fire, such as clear fire gardenia tablets, Huanglian Shangqing tablets, Sanhuang tablets, Yiqing capsules, etc. Do not eat spicy, too hot and too hard food, but also can drink chrysanthemum tea, peppermint tea, bamboo tea, honey water, etc. These teas also have the effect of reducing fire. If the blisters inside your mouth are small and dense, it means that you are infected by the herpes virus. If you have herpes stomatitis or herpes cheek infection, you can take anti-viral oral solution and Banlangen granules to shorten the course of the disease. If the herpes inside the mouth breaks down, leaving a congested, eroded ulcerated surface, it is recommended to use a mouthwash with anti-inflammatory properties, such as light salt water and tinidazole gargle. Also, brush and rinse your teeth carefully to maintain good oral hygiene.