Woke up this morning with blistered rash on arm

I woke up this morning and my elbow was bothering me. It felt like I had given it a rug burn on the sheets in my sleep or something of the like. I took a look at it and i had a roughly linear rash starting on my elbow that extends to about halfway up my upper arm. There are some raised areas in the rash, starting with a rather large blister at the elbow. The raised areas seem to become less severe as the rash moves down my arm.

My roommate thinks it might be a spider bite but I'm not so sure. I fell asleep on my laptop last night. Could it be possible that sometime in my sleep, I positioned myself so that my skin was pressed against the laptop's exhaust for an extended period and it burned me?