Bumpy itchy growth - please help!

I noticed my dog itching at this spot near the middle of his back. It looks like a cluster of bumps with the top being a little red (maybe from irritation from scratching). Yesterday, I went to the ER since he was vomiting and pooping a lot (yellow bile/foam at the end) and his blood work is normal though at that time I/we didn’t notice the bump. I don’t know if that’s related. Thank you for your help!

Hello!   Vomiting and lumps are usually symptoms of different diseases, some of them minor and some of them major, eg depending on the curcumstances, vomiting could be mild gasterenteritis or parvovirus or diabetic ketoacidosis, or any of multiple things in between.  A small lump could be an inflammatory reaction to something on the skin, or a papilloma, or it could be a malignant growth, or again, multiple things in between.  When a change to a skin lump and vomiting occur together, it is often a coincidence (a lot of dogs have lumps and a lot of dogs vomit).  However, vets' ears sometimes prick up when we hear this, in case of a degranulating mast cell tumour, which would be a cause for concern.  I suspect that the emergency vets would have mentioned this possibility to you if they were concerned (I know absolutely nothing else about this patient or the circumstances of the vomiting)  but it's worth being aware that such a thing exists.

Ps  one cannot diagnose a lump from its appearance.