I assume that an individual who got raped gets mentally shaken, but that's all, however serious the commotion may be it can be fixed by psychological monitoring and medications for sure. The rapist has a deeply mental damage though, he doesn't care about feelings, the pleasure guides him, actually I can't even believe that someone who have raped could become an ethical person.
Even if it does, they would need psychological help but in a different way. In many cases people are always jumping to the conclusion that rape is about sexual desire, but if the number of rapists that were women was equal to the number of rapist men, then no one would think that. It's a bit sexist towards the entire male gender. It's usually about dominant control, men may have a stronger built, which is the only reason why there are more male rapists than female. Rape is usually about power, and in a conflicting situation, this is what it can lead to. Like in the book "The Kite Runner", one of the boys raped the other boy because he felt he had power over him, to mark his stance, and for no other reason than that. That is caused by something very early in childhood that could easily be changed, he knew what he was doing, but he grew up taught that Shia Muslims from where he was originated were barely people at all. The victim obviously suffered from severe trauma that will never completely go away, but the rapist doesn't even feel guilty, and if they do, that doesn't necessarily mean they'll stop. The trauma from the victim may be more obvious, but the rapist has deep trauma they don't know about, and refuse to accept.
It really pisses me off that this question is even asked. Clearly both parties meed psycholigical treatment. One obviously needs punishment as well but both need psychological help. One because they deserve it and the other because thats how they are rehabed and are able to maybe become a contributing member of society which i thought was the point of a justice system. Plus its just the right thing to do. You cant operate a justice system on irrational decisions based in anger or emotion.
If that was the cause then anyone that performs a crime, rather it be menial or horrendous, deserves some form of psychological treatment. Criminals are people who can easily distinguish between good bad bet yet still engage in awful act for the sake of their own selfish desire. IMO, saying that a rapist needs more psychological help than the victim is practically similar to saying that they weren't completely responsible for their actions.
The rapist doesn't need help, he needs to be locked up in a prison cell. The victim has gone through a horrible tragedy and will need a therapist for the rest of their life. Even of the rapist needed help, honestly, they don't deserve it. We shouldn't start treating the scum of humanity as the victims, we should treat them like what they are, despicable criminals.
The rapist may not need as much psychological help as the victim (who is probably now traumatized for the majority of, if not the rest of, their life) who really needs some counseling, but that doesn't mean that the rapist can just be thrown in jail and let go when their sentence is up. Simply punishing the rapist is a terrible idea because it doesn't solve the problem that this individual has the capacity to rape, counseling them and seeing if we can solve the mental problems that made the rapist rape in the first place, that would be more beneficial to everyone than just locking them up.
The way you deal with a rapist is by grabbing a bamboo stick and using ninja smash tactics. The swiftness must be well-tuned with the angle. Maximum efficiency means more damage for less cost to the state. When you have finished beating them to a pulp almost on the cusp of death it's time to pour salt on the wounds and maybe piss a little here and there before you throw some meat for dogs to eat.