There is no chance that you will change your username instead you will ask the moderators to help you out but there is no assurance that they will help you immediately.
My advice: create a new account. I don't think you will get your handle changed.
If OP will change the account the previous account must be tagged as an alt of OP to prevent getting issues in future. Don't worry OP just a neutral tag as for reference this is your alt account.