I am 176.5cm tall. i was around 81 kg in may.then i decided to do excercise and now my weight is 72 kg.but dark color around my kneck,armpit,groin region and knuckles has not disappeared.should i loose more weight to see results?

https://www.mayoclinic.org/diseases-conditions/acanthosis-nigricans/symptoms-causes/syc-20368983#:~:text=Acanthosis%20nigricans%20is%20a%20skin,affected%20skin%20can%20become%20thickened. Your BMI is fine 23.1 I would not advise losing more weight . Would follow up with MD and check for insulin resistance, thyroid /adrenal, review medications and would follow up with dermatology for treatment.