Your vet will probably prescribe antibiotics & it shoud make a big difference almost instantly (a day or so). They can be somewhat painful but if you catch it early & get it treated nothing to really worry about. Some dogs only get them once in a great while while others never & some frequently.

just a thought in case it keeps re-uccuring:
My rott used to get bladder infections & uti's all the time, Once it would clear up about a few weeks later another would come along. We ran tests & x-rays, nothing. This happened for about 2 years straight (you can imagine how many carpets i had to replace) any ways she was on a pretty good food, & it never crossed my mind. Well I was working at the vets at the time so I got a great deal on good food. Then I quit & decided to change foods since the price between most good diets was about the same, and guess what, 3 years later and not one bladder or uti! Since then I have come accross this conversation with a couple other owners that experienced the same thing, and guess what they were feeding the same food I was feeding Raustyk. I explained it to them & they changed foods & bingo no more uti's for them since!