The hose clamp was over-tightened and not in the right spot, behind the barb. What I do in such cases is use a socket wrench as a dolly on the inside and carefully massage the metal to its original design with auto body hammers. Done it before, and on a former military vehicle..an M561 Gamma Goat.
You can try to pull it out to rough shape using needle nose pliers or similar. Then use the socket. To get the barb straight, use a smaller socket on an extension and angle it into the recess from the inside. Light hits on the socket will bring out the barb.
To finish it out, clean it off to bare metal, then use 50/50 solder to tin the area. Then using lead wire and CAREFUL heating, apply the lead as body filler using tallow as flux. Wooden spatulas cut from oak are great at shaping the soft lead while it is cooling. It goes on a bit mushy when at the right temperature so watch the heat. A large soldering iron can also be used to smooth it out. Then careful filing will get it smooth as glass.
Sorry, this method of body filling is a lost art. It was the norm before body filler and the origin of the term "lead sled". It still is useful for this repair. I've also done it on battery terminals.
