That’s a pollen sac that has started to open up. If it’s the only one, VERY CAREFULLY remove it. If you notice anymore repeat this process. But if you notice your plant over run with them. It’d probably be best to start fresh with a new plant. Unless you don’t mind seeds in your smoke. Because unfortunately my friend, you have a hermaphrodite. Sorry to be the bearer of bad news. It happened to me my first grow but I just kept picking of the pollen sacs, probably about 20 through the whole grow, but I eventually just didn’t see anymore. Can’t say that it will work for you. But if you want to keep it and try not to have seeds, that would be my advise. Otherwise, chop and start new or just let it be, if it’s the only plant in the area. Anyways, good luck with your grow and feel free to post a pic of the whole plant! Happy growing.