Paris Crawls Back on All Fours

Paris Hilton traded the Euro for the good ol' U.S. last night -- she spent the evening with Doug Reinhardt.

Wednesday night/Thursday early early, Paris hooked up with Cristiano Ronaldo -- who can forget our pic of Paris' ass as she mauled the soccer star?

But our spies say last night Paris begged Doug to take her back. She told him she loved him and had made a mistake by breaking up with him.

We're told she was texting him all night and then showed up at his house at 4 AM this morning, banging on his door. Apparently Doug succumbed to her charm ... which means he scored.