You had no risk for an STD. Nothing she did to you or you did to her could transmit an STD.
The substance between the head of your penis and your foreskin - could that be smegma? Was there an odor to it? How has your hygiene been? It could also be something called balanitis, which can be caused by a fungal or bacterial infection. If your girlfriend has a yeast infection, perhaps you got it.
Stress can cause night sweats.
If you have a visible lump on your jaw, you need to get that checked. Whatever it is, it's not from an STD, but could indicate something serious. It needs to be checked out.
Don't even worry about the massage encounter - there was no risk from it. Definitely get the white stuff checked out, and absolutely don't wait to get that lump checked.