The vet should have been able to make a fairly accurate assessment if this is a tooth issue or a tumour just by looking in his mouth. Looking at his face, I'd lean more towards a tumour just by how it's starting to displace his eye. Is the lumpy area firm or soft?
Would you be able to get a picture of his mouth with his gum pulled up, or inside his mouth? Watch for a yawn and be ready to take a quick picture.
Poor old guy. Oral tumours take way too many of our precious little ones.
* * * Nancy * * *
Retired from breeding
Rescue contact for both the Hedgehog Welfare Society and the IHA
Rescued over 70 (and counting) hedgehogs needing a new home