When Jane and Frost are searching Rory's car, they are in the trunk with the ALS and they see a spot that fluoresce. Jane says that it's blood, but blood does not fluoresce under UV light. It shows up as a black spot because it absorbs the light, not reflect it. What they saw could have been some other thing (semen) but definitely not blood.
The school reunion shows Jane as being in the class of 1994. She mentions while she was in school going on one date and seeing the movie Dumb and Dumber (1994), which was released in December of 1994. Since high schools graduate in the spring, it would not have been possible to go to this film while Jane was in school.