Strange lab draw today

I had to take LJ to the doctor today for repeat labs.  These were the follow up labs since LJ was taken off one of his immunosuppressants last week.  I always get so nervous when my baby has to go more frequently than normal to get his blood drawn.  On a positive note, the transplant coordinator in Boston said that his labs were improved today, so that was a blessing.
There was something else though.  When the nurses drew LJ's blood, these little red dots started to pop up on his skin, instantaneously.

 my baby's arm right after blood work

 I literally watched it with my own eyes.  This had happened the last couple of times we came for blood work, and when I asked the PCP.she said it was probably from holding his arm tight.  Sure enough, today, I saw it happen.  It scared the life out of me though to actually see them popping up.  I emailed Courtney (transplant coordinator in Boston) to tell her about it, and asked what she thought of this happening.  She did say to watch it to be sure it goes away quickly, and if it persists to let the doc know here at home, but she would give them the heads up.  She said it looks like "petechiae" and being that I never heard of this, I immediately went online.  I read so many things about these bumps, a lot of which were very scary.  It turns out though, that it was exactly what I thought, and the bumps came from the tourniquet being too tight when he was getting his blood drawn.  The nurses also use a heating pack, which may or may not exaggerate the issue.  I will be keeping a very close eye on it to be sure it goes away within a day or two, there is not doubt about that.  I tell you though, if it's not one thing, it is definitely another.