It should be noted that Build It! has only been anonymous for the past year. Prior to that, when builders' names were shown during the round, it would have been absurd to pretend to vote for your own entry because nobody would fall for it. Though it has now been made possible to convincingly "vote" for your own entry as what some think is a tactical advantage, it's not an advisable move if you want those around you to trust and support you in the future.
Of course, the fact that you weren't called out on it until after the round ended shows that people may not be reading the descriptions or looking at screenshots particularly closely. Both Raven and Son of the Serpent clearly state that they were built in Catalian Amusement Park, they're both built entirely on checkerboard lawn stripes for some reason, and Son of the Serpent can even be seen in the background of
at least one of Raven's screenshots (click underlined text to see image), so if anyone actually fell for your false vote despite the obvious clues you left pointing to it being your coaster, their attention to detail needs to be called into question.
Even though your entry won, I don't believe that it was your "vote" that caused this to happen. If you look at the posts from before the round ended, many people had positive comments about Arroyo and Dr. Mechanico, but you were the only one who had anything positive to say about Son of the Serpent. This suggests that most of the people who voted for your entry didn't base their votes on other people's feedback, but rather on their own personal preference. Therefore, you still probably would have won the round had you not attempted to garner votes dishonestly.