Certain diseases, such as skin cancer and lymphoma, may be increased by taking Mycomune 500 tablet. When outside, use protective gear and apply sunscreen to minimise unnecessary or prolonged exposure to the sun. If you have a sore whose one part does not look like the other, skin changes, sores that do not heal, unexplained fever, tiredness that does not go away, weight loss, or pain or swelling in the neck, groyne, or armpits, call your doctor.