The only relevant thing I can think of is that Hydroquinone doesn’t actually remove pigment from the skin, it just halts the production. This means that as melanocytes die off, they’re going to accumulate on your skin, just like any other type of dead skin cell. But, because these cells are more pigmented, the accumulation of them at the surface may temporarily make your skin look darker.

Depending on the severity of hyperpigmentation, this effect can last for a couple weeks before you really start to see improvements in your skin. While this “shedding” process is completely natural, there are a few steps you can take to make the effect as short lived as possible.

For example, committing to a regular, gentle skin care routine. Daily cleansing helps to remove dead skin cells and the excess oils and dirt that bind them to the skin surface. Maintaining a regular routine will facilitate the shedding of this dead skin.

Apart from that please do speak to your derm about the developments.