What do you do when a lingual vein in your tongue is pierced?

So I want to get a tongue piercing and I'm hoping I'm able to, but I'm curious, if the worst was to happen and it goes wrong, what do you do to not bleed out from one of the important veins being pierced? Also I don't have an obvious vein in the middle under my tongue from what I can see, but does everyone have it there, but some less prominent? I find it very confusing as to why some people can and can't have a tongue piercing.