Can you get a cold sore on your lips after they are sun burnt?

Yes: Sun burn can damage outer protective skin layer hence exposing to all sorts of viral and bacterial infections.

Absolutely: Any irritation to lips which chronically hold the herpes virus may prompt the activation of a new lesion. Wear a lip protection with sun block.

Absolutely!: Lip cold sores are usually caused by a recurrence of a herpes type1 virus, that lies dormant in your system until there is a stress. Lip sunburn is the perfect stress to bring back the herpes sores. You probably contracted the virus as a child. It stays in your body, "asleep", until at times of stress - fever, emotional upset, sunburn, etc - it causes new sores. These usually resolve in 10-14 days.