FREE: Pair - BLUE ANODIZED CAPTIVE BEAD 14G BODY JEWELRY

Most likely but I think it would depend on thickness of your lip and at what gauge you were pierced. Here's a gauge chart to know what the 18g looks like: http://www.eargaugesizechart.net/ AND I've added some pix too.
And Keep in mind the diameter of them, they are only 1/2" diameter -- The usual is 16g, which is 1.2mm (around). They usually pierce a 14 or 16 with guys, and a 16 or 18 with girls. An 18 is smaller, but can move around your face more easily so try to stick with 16g. Diameter always depends on thickness of skin below lip and lip area. Hope this helps. THANX for taking a peek & good luck bidding :D