Question about weight gain?

I've been dieting and trying to eat healthier, reducing fat and sugar from my diet. Especially fat. The area I am targeting is my THIGHS! oh, the thunder thighs. I am short, so that makes it all the more worse. Well, today we had a barbeque, since the weather was nice. The other mother that was there didn't eat much, but after dieting, those freshly grilled burgers just looked so gooood. I finally gave in and had one, with some chips. But while packing things up to leave, I looked at the box of burgers and couldn't believe what I saw. 230 FAT CALORIES in ONE pattie! How bad is this for me? How much weight will I put back on? Should I starve myself tomorrow, and then go back to regular eating? Thanks.