Cold sores (fever blisters) are small red blisters that usually appear on the lips and outer edges of the mouth. They usually appear after colds, fevers, exposure to the sun, stress and other conditions which cause the immunity of the body to dip.
They are usually caused by herpes virus which are latent in the body and can flare up when the immune levels of the body get disrupted.
Most cold sores will clear up on their own in a week to ten days time. You can use Vaseline or glycerin to provide moisturization to keep the cold sore moist. This also acts as a mechanical barrier to guard the skin and lips from irritants.
Topical analgesics/anaesthetics including benzocaine, lidocaine, benzyl alcohol, camphor, menthol and phenol help provide local pain control and may help reduce the itching.
Oral analgesics such as ibuprofen and acetominophen also provide temporary relief from the pain. Application of a Vitamin E cream may help in faster healing.
The pink area in the site where the scab came off will heal and regain its color even if it takes some time.