Guttate Psoriasis

Hi Everyone, My son who is 10 has had a few psoriasis patches and then couple weeks ago had a rash which by a week later was covered in Guttate on back chest and bits on arms an legs. He is now under a dermatologist and waiting to have light therapy. Scalp is really bad and red. We've been given enstilar and betacap and various other bits. Has anyone got any experience with this and any advice how to treat and what worked best for them. Claire