Thanks for posting your query. I have read it with diligence.
The risk of transmission of HIV
through unprotected oral sexual intercourse is very minimal. As far as I see your symptoms, it seems like a viral infection such as EBV.
Are you aware of the HIV status of the girl?
If you consider yourself being in high risk exposure, please go ahead and get yourself tested.
Yes, as you said, swelling of the lymph
nodes can be a sign of HIV infection but do not confirm the same.
I hope to have answered your query.