No one is immune to bad things happening to them. It doesn't matter how attractive or unattractive you are.
It won't make you immune to creeps and stalkers.
If you're attractive, more people will pay more attention to you. There will be more people who want to check you out because they're more curious about you.
It won't make you immune to an unsuccessful career and low salary.
There's too many attractive people who are poor or just in the middle class. If you have no ambition, your attitude sucks, you're not smart enough, and you're lazy; you won't make it far even if you are attractive. If you're applying to med school, the admission's office won't be looking at your face. They would be looking at your grades and accomplishments. It's the same thing with job applications.
It won't make you completely immune to depression and other mental disorders.
Maybe attractive people are less likely to develop depression and other mental disorders, but that doesn't mean it's impossible for an attractive person to have a mental disorder.
It won't make you immune to rejection.
There are plenty of possibilities of why you got rejected. It could be that the other person is taken, doesn't like your attitude and your personality, doesn't like your past, doesn't like your habits, and/or etc. Just because you're conventionally attractive, it doesn't mean everyone will find you attractive. It doesn't mean that every straight person of the opposite gender will be sexually attracted to you. For example, you could have an attractive face but they could be turned off by your height, race, color complexion, nose shape, face shape, or whatever. It's because it doesn't mean that all your genes will make a good combination with everyone else's genes.
It won't make you completely immune to all other medical disorders and illnesses.
There is proof that facial symmetry is what indicates a good immune system and it is true that attractive people have better immune systems than everyone else, but having a strong immune system won't make you %100 immune to everything single virus and bacteria that could ever exist in this universe. I rarely get sick and I am more likely to survive ebola if I get it because of my good genes, but I don't know for sure if I'm completely immune to everything. Attractive people are less likely to have other health problems as well, but again, nothing is %100 preventable.
It won't make you immune to bullying.
There are a lot of stories of attractive celebrities and models who were bullied in their childhood. Jealous people will root for you and perverted people might sexually harass you. Attractive people can be subject to sexual harassment. I was sexually harassed in middle school because I'm averse to touch and girls thought my distress makes me even cuter...
It won't make you immune to getting cheated on.
No one is immune to that. There are so many stories of attractive people, including celebrities and models, who got cheated on by their partners. If you're attractive, your partner could still take you for granted.
It won't completely prevent you from being in an abusive relationship.
An asshole can exist in any relationship. Your attractiveness might not stop them from hitting you or emotionally abusing you. My brother has been in an emotionally abusive relationship and Rihanna was hit by Chris Brown. Enough said.
Sincerely, it's me again, the brutally blunt honest 10 out of 10 guy