Exclusion and name calling in p1 is it fixable?

[MyLittlePeonies]

Has anyone ever had a successful resolution to bully with younger children. My son is having an awful time and the school appear to be making light of any issues. I know that's part of the problem if they are making little of it all. But he has lost lots of confidence.
We are not exaggerating it, which seems to be what they are implying.
The boys in his class won't play with him as they think he is naughty. I've heard a more than 3 or 4 tell him and me that he is bad sometimes,hes stupid, he's the bad boy, etc.
He himself tells me he is not good. It's heartbreaking. I've checked twice with the teacher since September and he has not done anything naughty. I think the label has stuck from a few issues last year and the boys have latched onto it.
They run away from him and throw things over his head so he can't catch it.
He has bitten his nails until they hurt and he has started bedwetting.

If I make a formal accusing of bullying then they will have to follow a set procedure, I think. Can anyone with experience of this help me out with what should happen then and if it's likely to achieve anything?
Not sure how long I should give this before I pull him out of there. It is so tempting.

[Ineverpromisedyouarosegarden]

I am so sorry you are going through this. Yes it can most definitely be resolved. Make an appointment if you have a partner see if you can both go in together. Write it all down before so you can list all incidents.

Your poor Ds