Psoriasis from injury to skin

I have had a psoriasis patch just below my knee caused from a skin injury whereby I grazed my knee quite badly and it never healed and instead formed a large white crusty patch. It appeared about 7 years ago and I've never been able to get rid of it. Since then Ive had other small itchy areas on my knee that sometimes can come out red and blister but heal quickly and dissappear. Recently due to the Corona Outbreak I started pulling up my zip up jacket to cover my mouth and nose where I didn't have a mask available and the zip has possibly rubbed on skin just below my lip and its formed a red mark that looks very much like the early stage of psoriasis but it hasn't formed any white crust it just has what I would assume to be all the hallmarks of what a red psoriasis patch would appear to be. It measures about 1cm wide but fortunately is partly hidden by my beard. I therefore have to assume that I'm prone to psoriasis when some areas of my skin is grazed. Does anyone else have a similar problem and is there anyway of holding an area back from turning into the dreaded white scaly patches?