PPP

I have Plantar pustular psoriasis (PPP), on my feet, I have had phototherapy and topical creams none of which have worked. I am now on Methotrexate only 3 weeks in and so far no sign of any improvement.... My GP thinks that the area may be infected as it is red raw and peeling like crazy and has prescribed antibiotics and some tablets to take at night, they were once issued as anti depressants but now are used to deal with conditions that are nerve triggered. At this moment in time the pain and discomfort is unbearable, my feet feel like they are on fire or that someone is holding a lighter to my feet and burning them, has anyone else experienced this and if so what did you do about it? Thank you Mary