How to reduce the black mark around the eyes?

Black bag of courage: Assumming the "black marks" are not a black eye from contact there is very little one can do to get rid of "allergic shinners". If congestion is controlled with appropriate treatment in time the darkness can fade. If vanity requires makeup can cover-up the evidence.

Make-up and meds: The quickest way is cover-make-up. We all have a bit of darkening under the eyes, but allergies sufferers have darker 'circles/bags' because of nasal congestion which hinder normal blood flow in the areas causing darker appearance there. Thus, treating allergies/nasal congestions often help reducing this--steroid nasal sprays are first line rx. So, consult doc for eval. Good luck.