Does alcohol thin the blood?

No: No but the effect on the liver will. It causes damage to it thus proteins formed by the liver are depleted which predispose to easy bleeding.

Not exactly: Blood actually doesn't get "thinned." what we call blood thinners are agents that decrease the ability of the blood to clot, usually used in people whose blood clots excessively. Alcohol also can impair clotting, both by damaging the liver which produces clotting agents, and by damaging bone marrow which makes platelets, the cells responsible for starting a clot in our blood.