Hey. Today as i was travelling home on the train, a lady ran past me with what appeared to be a syringe and needle in her hand. There were trackmarks on her arms, and she was eventually escorted off the train for being abusive. As she ran past, i felt what i thought was the needle, brush against my forearm. A small superifical scratch appeared, however no blood was drawn. It went red, like that when say a cat scratches you without breaking the skin down.Is this valid? Should i get post-exposure prophylaxis or is that over-the-top? Cheers.

Close encounter of the needle kind, but not exposure, since there was no access to your blood (skin remained intact). You now have one of the most hair-raising public transportation stories in your circle of friends, I'll bet. But you dodged the bullet. Cheers!