Regex to remove certain repeating characters but ignore others

Question

I am trying to write a regex function to detect if a character is repeated 3 or more times.

I am using

var regex = new Regex(@"(.)\1{2}");

This works fine, however I need to amend the regex so that it ignores the '.' character. I am unsure what to put in so that the full-stop character is not included in the regex match

So

"some string aaa" "some string with bbbb content" "some zzz string" would match

but

"some string a..." "some string with a content...." would be ok

Can anyone advise? Thanks