Inner side of my left cheek seems puffier more prominent than the right side. no pain. not a lump just looks bigger when i open my mouth is itcancer?

Unlikely: It is not feasible to provide a meaningful opinion without taking additional history, and physical examination . Cancer is unlikely. A slight asymmetry is not abnormal, e.g., breasts are usually of slightly different sizes. For good health - Have a diet rich in fresh vegetables, fruits, whole grains, milk and milk products, nuts, beans, legumes, lentils and small amounts of lean meats. Avoid saturated fats. Drink enough water daily, so that your urine is mostly colorless. Exercise at least 150 minutes/week and increase the intensity of exercise gradually. Do not use tobacco, alcohol, weed or street drugs in any form. Practice safe sex, if you have sex.

New?: If this is new, see a dentist or your GP and get it checked. If it's always been that way, no worries! The human body is asymmetric (as is all Fine Art) and one half does not look exactly like the other half.