How to Tell if Redness Are Scars from ALA-PDT Treatment?

I had an ALA(Aminolevulinic Acid)-PDT (Photodynamic therapy) treatment done and got a severe reaction with scabs and blisters. Some of the scabs and blisters came off early. I am left with these red areas on my cheeks for 5 months now. They were always red but level. Is this scar tissue or just redness? Is there a way I can tell? I had 3 V-beams but is is pink now so I assume I need more treatments. When I put pressure on the areas, blood goes away for that split second, I see my normal skin color. Thank you.