Maybe just tilt it back so the bottom part is facing up more.
The next heads that grow in however will do the same thing and you will only be able to rotate so much before you are flipping it upside down.
A good thing to do with acans is to prevent this formation from the get go.
Fragging them nearly flat on a larger plug or rock will ensure they spread rather than sphere.
Now in your case if you can mount it onto something that the underside can latch onto and begin to curve back up that would be ideal (and slow haha)
I was under the impression that Lps corals could have heads in shadow as Long as the majority is lit but I could be wrong.
It may just cause color changes in the long run, not sure. My acans all grow flat on the rocks.