Poor Social Skills

Question
Hello, my question has to do with my 1.5 year old puggle.  He is very playful and dominant with his closest family (us), but dogs are another story.  Since he's very social, I have tried to take him to the dog park on several occasions, but each time brings new terrors.  IF he is the first dog in the park, he is less afraid of welcoming new dogs as they come in.  However, if there are a number of dogs inside, he won't go in, will have his tail down the whole time, and will hide under the benches in the park.  In other words, he is absolutely terrified and is often chased by other big dogs, I'm assuming because they sense his fear; and the problem is never eliminated.  I think that he needs to socialize, but I don't want to bring him more trauma than he already feels.  Is there a way that I can eliminate his fear, either by continuous exposure to these dogs or some other way??

Answer
Your question was  Is there a way that I can eliminate his fear, either by continuous exposure to these dogs or some other way??

My feeling is that it's a 50/50 possibility.

Was he as a puppy (before 16 weeks old) well socialized around other dogs?  If yes, then you may have a good chance of success.  If no, then you may not be as successful.

http://www.berkeleyhumane.org/PDFs/Training/Critical_Fear_Periods_in_Puppies.pdf

It is possible to de-sensitize SOME dogs to SOME fears, but it's very time-consuming, takes a lot of patienc, and isn't always 100% effective.

http://www.marinhumanesociety.org/Behavior/Handouts/DesensitizationMethods.pdf

http://www.whole-dog-journal.com/sample/a_bark_in_the_park.html

You may want to try smaller settings at first, like play-dates in a friend's backyard with their dog(s), rather than the overwhelming situation often found in a dog park.