I need help!!!!

Ohk all you crocheters out there! I have been wondering about my blanket's first row and I really had a look at it 5 minutes ago because it was twisting a lot. It's not really that noticeable though the first row is tighter until I out it on the floor.... then the rainbow appears.

 If I lay it how the yarn seems to want to sit it has quite a distinct curve! and I started that first chain really loosely for me!

I can make it sit straight but it does buckle.

So it's kinda a vote/questions....

Does anyone know a way maybe to pull out the green without pulling out the rest? because the tension is fine after the starting colour it's mainly the starting chain that's stuffing it up! I'm thinking of crocheting a chain to the bottom of the purple row or something something that catches the bottom of the stitches. I'm tempted to try it to see if I can before pulling it all out.....

Is it too much work to fix it? Should I just undo and start again this time with a bigger hook for the chain and dc row? or just the chain?

I love how the colours are working but the fact the first row is pulling makes it difficult. I want to do this properly I want to be proud of it!

I may have just answered my own questions but please any advice would be welcome!

Happy Stitching, 
Caitlin