This isn't so much a rape issue as it is an issue of ANY false accusation. I've always personally believed that a person who makes a false accusation that is proven false should receive the sentence the accused would have received if found guilty. There is, however, a distinction between proving an accusation was false and not having enough evidence of wrongdoing to prove the accused is guilty. In the latter case, nothing should happen to the accuser. You must *prove* the false accusation.
If, in this case, the accusation was proven to be false, I absolutely think he has cause for damages. Not that he's likely to collect $25M. I wouldn't even be surprised if any civil suit was tossed because the courts don't want to discourage accusations, especially given the current climate.