Welcome to HCM.
Th chances of transmission of HIV
through saliva while kissing are very very less. But , there is a possibility of transmission in case if both had cuts that are fresh .
You have mentioned that you have mentioned that you had a cut on your lip. In case if the person you kissed too had a cut then there is a chance of transmission of HIV is around 8-10% but not 100%. Dont worry as you have started PEP. Just wait for 3 months and go for HIV serology to confirm transmission. Getting tested with in 3 months does not reveal anything and result in false negative ( 3 months is the window period).
Hope you ar not infected with HIV.
Be careful and avoid sex with such people.