There seem to be two cases where hickeys may have caused strokes.
One in 2010 in New Zealand and one in 2016 in Mexico.
The case from 2016 is probably too recent to be mentioned in any papers, but here is the case report for the 2010 case, published by the New Zealand Medical Association:
> We report on an interesting case of blunt carotid artery trauma caused by a love bite. Blunt carotid artery trauma can lead to arterial injury, thrombosis and cerebral embolisation. It is a rare phenomenon and diagnosis requires a high index of suspicion. Current literature suggests a conservative approach to treatment with anticoagulation. Most patients achieve a favourable outcome especially when initial neurology was non-disabling.