When you raise the water temperature you accelerate the ich reproduction cycle. If you just wait and do nothing to treat the fish don't you believe the fish will soon start dying from ich?
Here is something for you to read and I did the same thing as what "Flower" did who used Xtreme garlic and I had the same result to save my blue and yellow tang. The thing to remember is that "ich will die without a host". With that belief I treated my tank with Xtreme garlic for several weeks may be a month or so and they all live until now. It was about a year ago.
They ich dies indirectly by starvation since Xtreme garlic boost immune system and ich avoid attaching themselves to fish.
killing ich with high temperature