random purple spots on inner elbow

[.pearl.]

so yesterday i noticed that i have 4 small circular spots on my left arm, inner elbow. they are purple...
i have NO idea where they came from...the only thing i could really think of was that i did arms on friday. according to my workout plan i was supposed to do biceps using a machine but for the past 2-3 weeks i've been using DBs b/c the machine made my elbows hurt-specifically the inner elbows and so i switched..
when i did biceps on friday from the first 3 reps my biceps were killing!!!!! they felt like they were being torn apart (not sure how to correctly explain the feeling)...and i was at a lower weight! i usually do 15lb DBs but i was using 10lbs! (last time they were also sore, though not so quickly) i worked through it (i thought maybe it was a new level of "pump" that i hadn't experienced before lol) but now i'm think that maybe i shouldn't have...lol

i don't think i have overtrained them-i work them out once a week, and that's the only bicep move i have...

i was just wondering if anyone has experienced this before? (the spots or the tearing feeling)

i will monitor the "bruises" for a few days if it doesn't get better i'll go to the doctor...

thanks!