Hello, I can understand your concern for skin darkening. After reviewing your query it is quite obvious that you have had dengue fever and after taking medications you got skin darkening. It is quite common to find skin darkening after long term illness or after taking medications. This type of pigmentation remains for few months and then subsides by its own. It is quite important to have sun protection in your case. I suggest my patients to use a sunscreen daily over the exposed area. It is should be applied for two times daily. Try to have sun protection to avoid further darkening. I suggest you to meet a dermatologist to take further guidance. All the best