Answer:
having an ongoing medical treatment
Explanation:
Exposing your skin under the sun is actually not bad for your health because the sun is a source of vitamin D. However, long exposure is bad for health. It may cause "sunburn." This condition is the skin's reaction once it gets exposed too long under the sun. It can cause several symptoms such as "having pain and discomfort." This condition is considered short-term because it can go away with proper treatment.
However, "having ongoing medical treatment" could mean that the person must have been continuously been exposed to the sun for a much longer time or frequently. It could mean he/she has developed skin cancer or is treating a cancerous lesion. Therefore, this is considered a consequence of a long-term injury. He needs to have more patience as it takes quite a long time for the body to heal and sometimes, it doesn't heal at all (for late-stage melanoma).
