That really depends on what you mean by drops. Are you talking from the 200 range to 175? Keep up what you are doing, adjust carbs, move more if possible, and keep taking your meds as prescribed.
Or are you talking 120 to 56? Of course eat or drink something to correct the low, retest after 15 mins to make sure it's headed in the right direction. If it's not going up much or at all, drink/eat more of your correcting option, retest again at 15 mins.
If this is a one off thing, don't worry, but keep in mind that you need to eat regularly, to help prevent lows from happen. If this is happening a lot, have your doctor look at adjusting your meds/insulin, to help keep this from happening.