Red itchy bumps and rash on legs, arms, and elsewhere

Hello, 

A few weeks ago after a day at the beach and getting a sun burnt on my shoulder (not sure if it’s relevant), I noticed red bumps showing up all over my legs. Now, they have spread all across my calves, biceps, forearms, feet, and a few on my torso. I have checked for burrow marks using ink and did not see any. The bumps are pustules I believe. I have dry skin and I can see where blisters have popped and crusted over on some. However I have no blisters currently on my body. The bumps on the back of my calves and underside of my knees have developed into large clusters and are very itchy. I had been told previously by a doctor (not a dermatologist) that I had psoriasis on my elbows and knees when I was younger, however it has remained mostly no problem. Any information would be useful as to what this could be, and any ways to treat it (I have tried Epsom salt, tea tree oil, lotions, aloe vera, and I’m aware that calamine lotion and antihistamines will help with the itch). I am not available to meet with a doctor for just over a week so any input helps. Thank you.

That sounds like scabies.  Permethrin should do it.  Some strains have developed a tolerance to these meds, so if it doesn't work I would recommend paraffin aka kerosene.  It sounds scary but if you do some research you will see that it was used frequently back in grandma's day for effective removal of parasites and for open wounds.  I have even used it on my face with no side effects, Wash all of your bedding and clothing you have worn and treat everyone in your household.