Will was apparently hit so hard by Bo that he needs to ice his face, however, there is no bruising.
After Jazz loses all their money to Lola, she offers Will a chance to win the money back "double or nothing." After Will wins, he tells Carlton he has the money to get the car back. Will had $30 and Jazz had $20 to begin with. Double or nothing would have been Lola doubling the $50 she won from them, or Will getting his money back. So all Will would have is the $50 he and Jazz started with, nowhere near enough to pay the $300 to get the car back.
Will orders a pizza on his cell phone while driving from Los Angeles to Nevada and says he's driving "north on I-80". I-80 runs east/west and originates in San Francisco, not Los Angeles. While this is true that I-80 runs mostly east/west and originates in San Francisco, it does run north/south in Nevada when driving from Bel Air to Reno. While many may assume that Will & Carlton are going to Las Vegas, it's only ever stated that they're going to University of Nevada. Given that they're traveling north on I-80, it's clear they're visiting University of Nevada - Reno, not Las Vegas.
When Will starts to stretch before the fight, his foot catches on a piece of the fake ground and flips it up.