All you can do is wait it out. Don't try to force it back, it'll just get worse. And if it is your nose that's making your voice odd, if that's what you mean, then Yashica's right, just microwave a few potatoes in a wet paper towel for about three minutes, and then cover the bowl and your head with a towel or blanket so the steam doesn't escape. It sounds weird, but that's how we Russians do it. We use potatoes for everything.
Blocked nose can change your voice,take steam regularly to make it better,gradually your voice will be fine soon after doing this.
