What stds can be transferred by kissing and hickeys? made out with stranger at party and freaked out about it.

Mononucleosis: You can get mononucleosis from kissing an individual who is infected. Oral herpes is another possibility.

Non-Genital STDs: Your main risks for std transmission from kissing and "necking" would mainly be herpes type i, mono or cytomegalovirus. CMV is not a concern for healthy individuals and mono usually causes a prolonged, fatigued illness. Herpes, as they say, is forever. Unless the stranger in question had an obvious sore, it is a low risk that you have contracted it.