Reaction on snout

About a month ago my dog started getting this reaction on his nose. I took him to the vet and he said it was my dogs bowl(plastic) So I changed it and the vet gave a steroid shot. It got a little better but now we're back to point A and it looks the same as before. Any ideas what it is or what could help ?

Doesn't look like a happy face. Your vet was correct with recommendations to remove plastic dishes as they often cause local allergic reactions that can be similar to those lesions. However, there are many other skin conditions that can also appear like this. Probably going to need a culture and biopsy to get to the bottom of it. Most likely a nasty infection or an immune-mediated problem like discoid lupus or pemphigus.

Are there any toxic plants where you walk the dog? Nettles or something like that?

I agree, first thing I thought of was Pemphigus. Some used to call it 'Collie Nose'. It's an auto-immune disease, and often made worse by a lot of exposure to sunshine.