Hydroquinone is a double edged sword,if not used properly it can lead to increase in pigmentation, stop using it for now , consult a nearby Dermatologist to find out proper way and duration of use of any medicated skin products, always use a sunscreen spf 30 and more to prevent added pigmentation. Existing pigmentation can be treated with depigmenting creams ( non hydroquinone) , chemical peeling or lasers once the redness part settles down.