I wanted to leave some feedback, I love these short stories or flash fiction! Please keep in mind that my advice is aimed at helping people improve and horror/thriller is not my best genre… so what I write may be very wrong, and I’m not intending to be negative.
I like that you start with such jarring action! You don’t have a lot of space, so getting right to the point is important here. However, I’m very confused at how you kill this poor fool. You first tell me your knife is in his back… then you have yourself strangling him… then you talk about him being decapitated… so did you stab him in the back, then choke him, then cut his head off? Nothing wrong with that, but since the story is so sort, I feel like adding more detail to one method might be better than using 3/5 sentences on different ways to kill someone.
Like for example, I really want to know why his arms are around you! Did he think you were hugging him and you stabbed him in the back? That would be brutal… and it’s okay to leave that to the readers imagination, but you could leave out another kill method to describe, as an example, the look or horror and hurt in his eyes when he realizes that you didn’t love him you just wanted to get close enough to (literally) break his heart.
Another small thing is that you started the first two paragraphs or sentences with “My”. This isn’t a huge deal, but the first word is the first thing your reader sees. You could mix it up to make that different and possibly something more exciting. An example would be, “Hand prints belonging to me are red on his throat while his eyes…” This just emphasizes the hand prints more by putting them first.
Another thing I think this story could benefit from is some hint as to why this happened. Like we don’t know if the person who killed him is crazy, a hired assassin, or a vampire. However, you could make it clear or just imply. Like if rather than licking blood from your fingers you suck it from his neck that’s pretty clearly a vampire. But it could be whatever reason you want. I will acknowledge that sometimes not telling the reader why something happens adds to the horror/thrill, so if that’s what you’re going for please disregard this paragraph.
Overall it is a creepy story that fits the prompt perfectly. Well done! I especially liked the touch about his lifeless eyes still watching you. That’s terrifying to imagine.