I'm thinking of getting my ex-girlfriend's name tattooed on me because I lost a bet
That's a bit extreme, what exactly were the terms of the bet?
I promised to do it if my local team wouldn't win. They lost unfortunately.
While you might have made this bet in fun or in the heat of the moment, I think the best thing to do is admit that it was a sill wager and refrain from getting the tattoo. That's something that will be on your body forever and there is a high probability you will regret it tremendously.
I can live with that.
Ultimately it's your call, but it'll be something people ask you about for the rest of your life. If you must get a tattoo, perhaps you could get something more reasonable. Regardless, you shouldn't feel obligated to get any tattoo.