Yes, you should visit a dermatologist as they are the experts with injuries to the skin.
I also recommend that you immediately stop using the bleaching cream. Avoid the use of hot water as well as this can worsen the condition.
It sounds like you’ve probably developed inflammation/burn injury of your skin (redness) and then post-inflammatory hyperpigmentation (darkening of your skin), or PIH after overuse of the bleaching cream.
With prolonged exposure to hydroquinone (an active ingredient in many whitening creams), another rare but serious side effect is a condition called ochronosis where the skin develops darkened gray/bluish patches. This is more likely in individuals with darker complexions.
Any bleaching creams that contains hydroquinone should be used for a maximum of 2-3 months. It should not be used for longer than 6 months.
Once your pigmentation has improved, the best thing to do would be to avoid sun exposure, and to use a sunscreen with zinc oxide to protect your skin and prevent it from re-darkening.
Cheers
