One of the possible side effects to having filler injected into the lips is an outbreak of cold sores. Trauma to the lips (needles) can cause the virus to become active. If you are considering getting this treatment in the future i would speak to your doctor about a oral medication that you take before your injections that can help prevent an outbreak ( Valtrex) .
Blisters and peeling of the lips may be due to fever blisters. If one is prone to fever blisters, trauma may trigger and an outbreak occur. Seek medical attention. Medication can be prescribed to help this problem heal. In the future, you may want to begin the Valtrex or Acyclovir 2 days prior to injection, the day of and 2 days after to alleviate this type of outbreak.