Is there a dental condition that could cause swelling under the lip? it will itch for a.second.then swell then go away cracks at corner of mouth to

Psychogenic diseases: symptoms are not a sign of illness, they are the mind's ability to produce the flight or fight response which gives rise to many physiological changes include dry mouth, swelling under the lip, etc. Depending on the cause of your psychogenic disease symptoms, your health care provider can recommend appropriate referral.

Angular cheilitis: Could be either an impetigo-type skin infection or a yeast infection or both. Try an antibiotic ointment alternating with an antifungal cream like clotrimazole and see your primary care doctor for further treatment. It can also happen from malabsorption or malnutrition. B-complex vitamin supplement and iron may help. Also, avoid lip-licking and moisturize at night with lip balm or vaseline.