Most Helpful Girl
First of all, hating on her just shows that you haven't moved on. The fact that you even think to make her jealous is clear enough to tell that you aren't over her yet. Cool down. Accept that it is over. While she is having fun with her friends and (probably) her new boyfriend, you are here depressed thinking about how to take revenge on her. It makes you look pathetic.
To answer your question, I don't think she'll get mad. In fact, she'd be laughing, poke fun at you and if she is really a ' hot bitch' as how you described, she'll be telling her friends around that you are still not over her because she is hot. Also, she'll know that you are just settling or using that 'ugly' girl as a rebound, maybe for sex too. She will think that you cannot get hotter girls than her. It is not fair for the 'ugly' girl.
The best revenge that you can do is do not bother to care about her. Move on and get over her then you can try looking for a hotter girl. If your new girlfriend is hotter, she'd feel something, and if she doesn't, leave her alone. It's over dude.
Most Helpful Guy
The answer is no. But if you wanna do that, it will make you a worse person than you ex. Please dont do things to others that you dont want others do to you.