If the eyelashes are on the top, it means either the top tension is too high (not likely as the thread would prob break first) or there is not enough tension on the bottom. Check to make sure you have the bobbin in correctly (thread winding off the right way - check your manual) AND check to make sure the thread is going through the tension device properly. There are ways to check the tension of the bobbin inside the bobbin case - it should just drop with a bit of resistance when you hold it up by the thread, and not unwind freely. If you have a front or side load bobbin that is. Top load bobbins are a bit tougher to gauge. Check your manual, and also check out YouTube videos on "bobbin tension"