Can you help with severe lip sunburn after Accutane? (Photos)

It has been 3-4 years after accutane and I continue to have severe lip sunburn. This did not occur prior to accutane and since taking it, my lips get severe sun burn. It usually takes a week to heal after getting severely red and getting blisters on my lips. I have tried to use sunscreen chap stick and reapply. It helps a little, but does not solve the issue. Please help, this is a major inconvenience and I deal with this multiple times every year.