I ampraying for some help here guys!!!

Our dog, parson terrier cross, had a bad experience as a small puppy with another dog. (Before we had him so details arer patchy). We have been told that if dogs have a bad experience in their first 16 weeks, when brain cells are forming that they never get over it. He is gentle and obedient in every other manner of his life and character.

He is petrified of other dogs. I cant express that enough... This shows itself as howling, barking, lunging, throwing himself on the ground, and then this morning - his frenzy was so bad that he actally bit my leg (and drew blood).

We have seen "professional" dog experts who have given us an array of various techiniques - none have worked, in fact in the last 6 months - I would say that whatever we have tried has now made it worse.

Has anyone out there tried a technique that has worked?
I would LOVE to hear from you.