How to get rid of white light reflection and make it same as background?

Sorry if the image below is disturbing. It is an image from the colon (from kvasierseg dataset). I want to remove all the white light reflections or make it the same as the surroundings. What should I do about it? Or is there any other way I should follow? Thank you.

this is to be done with an optical filter, not with digital filtering.