I just made caramel sauce using 1 1/2 cup brown sugar, 3/4 cup butter, and 1/2 cup milk. I was supposed to use 1/4 cup milk but i poured in extra by accident so I doubled the other ingredients. But my caramel sauce came out grainy and buttery, it also crystallizes as soon as it cools. What can I do to fix it? 
My recipe called for a cup of sugar  6 tbsp. of butter and a half cup of heavy cream. My sugar turned into a mess while heating on medium heat.  It never melted but seized into little chunks. Then I began adding my butter and it got worse.  I took it all out of the pot and added a splash of water to the pot first and let it heat up and put the chunky little bits back in the pot and let it boil for a few minutes. I added half of the heavy cream and it began to smooth out.  It was still somewhat grainy so I poured it through a sieve.  Voila.  It worked fine.  I have smooth caramel sauce. Just plain water did the trick.   