We've had chicken pox here for the past several weeks - it was about day 3 with the first one when I was "sure" it was chicken pox. FWIW, 2 of our 7 didn't have the vaccine - they both got chicken pox as well as one of our dd who did have the vaccine. Our 11 year old dd, who also had the vaccine, ended up with shingles.
The first dd who got them had what looked like bug bites, but then they ended up scabbing over. She only had a few pox that had the clear liquid in the center. The dd who had the vaccine had pox that looked more like bug bites, also. The ds who got them had the classic case - low grade fever for a day before and then broke out starting in the scalp, face, trunk, then extremities. Almost all of his had the clear fluid in the center before they crusted over. It was the 2nd day of having the spots that they started getting the fluid in them.