Pants Small

How do I get pants that are a little small on me to fit me?

I have this pair of jeans that my mom bought for me on Saturday, and they don’t fit. It’s the size I normally wear, but aparently, the sizes ran smaller this time. And I want to wear them so badly. What can I do that will help make them fit? Please help!
How do I stretch them? D:
I can’t exchange them over easily, because I’d have to travel about 40 miles. :/

You could try and stretch them, but it probably won’t work :/
If the store is close, exchange it for a bigger size.

Big Belly, Small Pants