HELP! Dog Question. What do I do?

Click on the pic to see the slobber rope!

I posted a while back about how we adopted a Cocker Spaniel from a family that didn't want him anymore. His is eight years old (almost nine now) and cute as a button.

Of course, now that we are taking care of  him, he is starting to have problems. For starters, he has recently began to drool out of the left side of his mouth. It is a very thick mucous that just about eventually reaches the floor and that's about when he does one of those dog shakes that flips his ears back and forth. You know, like after a bath when they want to rid their bodies of excess water.

But when he does it, that long piece of slobber wraps around his head a few times and gets all matted into his hair. He doesn't do it every day. Maybe every two or three days but certainly often.

Anybody know what the heck is going on here? Did we just get the dog right as he was entering his "senior" years?

AND, I just noticed he has just smaller than a baseball sized cystic mass under his left hind leg.  I just trimmed him less than a month ago and there was no mass there. By palpating it, and working in the healthcare field, I'm pretty confident it is purely cystic (fluid filled). It is easily squishy and moveable. He doesn't like me to squish it but he doesn't yelp either. It is right where his left hind leg meets up with his body, kind of on the underbelly, as it were.

Any ideas?

Update: June 2012, I just noticed the other day that Kohl hasn't drooled in a while. Don't know what it was but it has completely stopped. Weird, huh?