Bilateral cheek swelling or puffiness from inside the mouth can have several causes. One common reason is the parotid salivary gland, whose duct opens on the inner cheek â if temporarily blocked or irritated, the cheek can look swollen. Another common cause is habitual teeth clenching or grinding (bruxism), which causes the masseter muscles to enlarge on both sides. A white or raised line visible on the inner cheek is often called linea alba and is a benign finding from cheek biting. Since both sides are involved and it comes and goes, these are typically benign causes, but any persistent swelling inside the mouth should be examined properly.
Next Steps
Please visit a dentist or oral physician for an in-person examination of the inner cheek to confirm the cause. Please consult me directly on Practo for a detailed evaluation.