Natural wooden branches, an iodine block and a cuttle fish, provide grit for them to nibble on as im guessing this would also help
Get the vet to trim it for you and keep it up as his/her beak may grow at a faster rate than other budgies, keep on top of it and it should be ok, so long as the birds eating and drinking ok it wont be a serious problem, but it may make him/her feel a tad uncomfortable.
Best of luck with it and hope the vet does a good job
R.I.P Louis. In my heart forever and always <3