What can be done to relieve a swollen face on my left side of face from a toothache gum disease?

See a dentist ASAP. Unlike some other types of infection, a dental or gum abscess will not get better on its own and must be treated by a dentist. Do not delay.
Swollen face. A swollen face as a result of any dental infection can be resolved with proper appropriate dental treatment and antibiotic coverage along with your own body's healing power. The cause and the extent of the problem will determine how best to treat it.
Treatment. Please see your dentist immediately to be evaluated. You appear to have an abscess and in needs to be treated at once. Make that call and feel better soon...