Yeah this is bad ,your friend certainly made everything worse! I had the same "worries" with my guy but I was able to make sure he never got that first bite!
This is what I did, fear or aggression same deal is on Fearful Dog Blog. I did use a fabrick muzzle on walks in cool weather for a brief time. He learned I had his back and his place was behind me when I spoke to someone,it worked!
But certainly a trainer is in order...sorry this happened!
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