What do I do with a damaged page?

I have one page in my PDF that has problems with a couple of lines. Only the lower portion of each line displays, and only a portion of the line. This problem shows up when I display the page in Adobe Acrobat Reader, so it’s a page error.
How do I mend this page? I tried retyping the problem text, but the problem is unaffected. I tried cutting the unit of text, but when I tried to paste it, I got a message saying that I didn’t have the required system font (cidfont+f4).