I have a small lump which is dark purple after my boyfriend gave me a hickey. will i be ok or will this cause a stroke?

This would be a collection of red blood cells collected under the skin that will dissolve over time and be absorbed by the body. It is not a risk of a "clot" that would cause a stroke. Those form inside big blood vessels, there is no relationship between the two processes.

Skin lesions do NOT cause strokes as the blood vessels involved in etiology are unlikely to be harmed by a "hickey".