In a word, malignant.
exacerbation; also called flare
Malignancy (from Latin male "badly" + -gnus "born") is the tendency of a medical condition, especially tumors, to become progressively worse and to potentially result in death. A malignant tumor (cancerous tumor) is one that is invasive and can spread to other parts of the body. In contrast, tumors that stay localized and don't spread are called benign. Benign tumors may grow quite large and can do damage, but they do not usually spread through the bloodstream or lymph vessels to other parts of the body.
Sometimes they change in color, sometimes they grow, if you find something that looks too dark of might be questionable you should go to the dermatologist before it gets worse.
Progressive medical terms means it will get worse.
Getting worse.
deteriorating
The term literally means growing worse and resisting treatment. It is used as a synonym for cancerous and connotes a harmful condition, that generally is life-threatening
Seek medical attention
Worsened is a modifier meaning something became worse, or was made worse, than it had formerly been.
because you may become worse
Decline
to change, or grow, it can be better ,or worse, but basicly to change