The tomato garlic soup I made is too spicy (too much red pepper flakes). How can I mellow it so it's edible?!?

Bit of sour cream as you would with a chilli? Kind of cream of tomato soup...

Add some chunks of peeled potato and remove later, also a pinch of sugar, and if you can add another batch of the same soup without the pepper.

I did the same thing last week, you might wanna add light cream and some boiled carrots puree.

Do you have some more stock (or even water) to dilute it?