Could be that in the past you used to much pressure on the dog. That happens way to often. I would hesitate to use the lip curl method, especially if you would like keeping all of your fingers intact. You might try starting over with a soft sell and use very little pressure as he over reacts. If the dog scares you and you back off then he is running the show. Like TY4 said the toe hitch might be suited better for you and the dog.