Someone help please????????

So i have this thing on my arm & i have no idea what it is. It started out like a little red bump, looked like a bug bite, than it turned into this ->http://tinypic.com/r/2yux3it/6 <- eventually it got real itchy and a little bit painful and was getting worse so i went to the ER ( Someone said it looked like shingles but it's on a weird spot.. my elbow ..) & when i went to the docs they could not figure out what it was. they said it was no shingles. they took a few swabs of it but i haven't heard from them? anyways... it turned into a scar now than it got worse! turned into this -> http://tinypic.com/r/oaxkxu/6 <- it is itchy. and my arm is sore. the puss coming out if clear. and there is little blisters. and it is really red and swollen! i am pregnant... and the docs gave me medicine for it ( even though they dont know what it is) im starting to worry! i dont want it to spread!!!! anyone know what this could be or have had something similar??? help pleaseeeee.