I kissed somebody on the cheek (cheek to cheek) and i noticed afterwards that he had a cold sore on his bottom lip. what are the chances of me getting?

Probably low risk: Herpes isn't all that easy to transmit. The brief contact you describe is very low risk, even if his cold sore contacted your cheek. Also, many adults have had HSV1 from childhood, the cause of oral herpes, whether or not they have had known symptoms. If you were previously infected, you can't catch it again. Be on the alert for oral or facial blisters/sores in next 10 days, but very unlikely.