I don't know the details of what happened between you and Sam, but your apology isn't mine to accept. It's for Cris, and for Sam, and for Neil. I am a bystander only. I am glad to hear you're sorry, however.
I do think Neil genuinely cares about you, so staying away from him won't solve this. If you care about him, don't waste your time apologizing. Give him an opportunity to prove himself, and prove with your actions that we've all got you wrong.