First, you're probably feeling pretty guilty and your stomach may hurt so have a nap or if it's late at night just go to bed. When you wake up, make sure to be gentle with yourself and be kind, as you would if your friend was in this situation. I know it's hard, but it's important.
Have a light snack if you're hungry and drink some tea or lemon water, and have a long hot shower. You can do stuff to distract yourself too, like listening to music that makes you feel good or doing a craft, or playing a video game etc.
Don't restrict more the next day!! This will get you stuck in a binge-restrict cycle. Instead, eat as much as you normally would the next day.
It's okay to binge, it happens to everyone and it won't set your progress back very far. You will be okay I promise, I love you and it's not your fault. <3