Thanks! I found it when searching google. When I put advantage multi and bad breath, several accounts came up. Seems folks were saying it in other forums, doesn't mean it is so though, hence the reason I thought I would ask here. We already went to the vet, had to go for a follow up anyway. She did not seem concerned. She checked his mouth and he is cutting some teeth so she said it could be due to blood and I do know he is bleeding some evidenced by his chew bones and have read some metallic smell can be due to that. I just found it weird when I smelled the area I put the advantage multi on it smelled the same way. No he did not or could not lick that area. This was a week or so ago when it was applied. I was also thinking maybe it was his food but he has been on this food now for a while.
Funny too as tonight all of sudden I no longer smell it.