Once the airlock runs backward, the mead is either finished, or stuck. The best ways to determine this are to compare gravity readings, or to taste it. If it tastes good, and not horribly sweet (like raw honey) and has noticeable alcohol, it is probably done. Or, if your first gravity reading and this one are far enough apart to account for the alcohol percentage that your yeast usually produces.

If it's not done, you need to work out possible reasons that it quit, and try to get it restarted. If it tastes and/or measures finished, you can make final adjustments and then bottle, but there is no need to hurry. Be patient. It needs to age some, and it will do that in the carboy just as it will do in bottles, however, in the carboy you can still adjust things: You should be able to read through the carboy, and a flashlight should shine through clearly. Sneak a tiny sample out with a turkey baster or something similar that is clean. Does it have nice aroma? Would a little more acidity help to brighten the taste? Is it sharp, and maybe a touch of vanilla would smooth it out? What would one or two drops of lemon juice do? The possibilities are staggering. Just try tiny pinches, or single drops with a toothpick to adjust the mead in your sample to see if you like it first before you adjust the whole batch.

It might not need anything. It might just be done!