Nothing too fancy, but you should be able to apply bandages and gauze in markings form if you wish to.
Mirror/barber scissors like menu, but for bandages, maybe with restriction on marking color to make it have tint of the blood color the person has.
As for the roundstart markings, its more on case by case basis if it were to be troublesome, but probably there should be some method to get gauze that has any colour…
And all this would be opt in, if you during treatment instead of just clicking on someone with gauze, right click them and use some Bandages action, applying marking would initiate healing too.