I had a tooth extraction 3 weeks ago and i gave oral sex to a guy last night can i get hiv from this if he has it? he did not ejaculate in my mouth.

Possible: Assuming that your oral wound is still healing, and realizing that most body fluids can contain the HIV virus (including his emission ("pre-cum")), there would always be a risk. always practice "safe sex."

Not likely: At least from the tooth extraction site. While you can still feel a depression where the tooth was, after three weeks you tissues would have healed over the site.