Hi Doctor, i had oral sex with my friend on

Patient: Hi Doctor, i had oral sex with my friend on 14th october and my penis was wet when i touched her vagina and that time she was also wet….i had not inserted my penis in to her…just touched outer part….her period were supposed to be on 28th of oct but it didn’t came….she is worried….and she took contraceptive pills today….will that effect…..not sure what could be the reason for delay in period……what should we do to avoid any sort of pregnency

Doctor: