Occasionally on some sensitive skin types, hydroquinone can cause inflammation which can lead to hyperpigmention. Hyperpigmented areas of the face are more challenging to treat in patients who tend to have darker complexions and more natural pigment at baseline. If these areas changed only recently, they may improve over time naturally if kept out of the sun. It is important to wear sunblock and to protect the areas when outside. Energy-based treatments such as laser and intense-pulsed light are options if the dark areas have not begun to fade after several months, but again there is a risk it may make skin darker or too light compared to surrounding skin. For the best treatment options, it is important to visit an expert for an in-person examination. Hope this helps!
Johnson C. Lee MD