The "blue" on the edges is painters tape. It's used to mask of any ares that you don't want painted, comes in different stickiness and can get it at any hardware store.
For tape not sticking to your mask: Read the directions on any paint can: Clean & dry surface. REMOVE dirt, grease, etc...
any paintball residue from getting hit on the mask will not make the tape stick, clean surface with any alcohol, (denatured or isoproponol alcohol) to get rid any contaminants.
You don't have to use tape on the whole mask, just the areas closest to the area you want to paint. I have used newspaper and plastic bags to mask off larger areas that I did not want paint to get on.
I just takes time & patience to mask of the ares you want painted to have a great looking professional looking paint job.
To all the guys that have pictures of your mask painted...... GREAT JOB GUYS!