Give it some more time. If the smack pak swelled up initially the yeast are likely still alive. Check the temperature around the starter, if it's too cool, the yeast won't grow that fast. Ideally starters should be around 70-75F for good growth.
I almost never see a krausen ring, if the starter is stirring fast, it gets broken up as fast as it forms. I look for colour change in the wort, going from amber to butterscotch, to know there is growth.
Turn up the good, turn down the suck!