diff --git a/CHANGES.md b/CHANGES.md
index 79e7b0b1444..17decf5fe05 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -26,6 +26,8 @@
 
 <!-- Changes to the parser or to version autodetection -->
 
+- Fix regression where certain complex f-strings failed to parse (#4332)
+
 ### Performance
 
 <!-- Changes that improve Black's performance. -->
diff --git a/src/blib2to3/pgen2/tokenize.py b/src/blib2to3/pgen2/tokenize.py
index d920d0d7c01..07b2ebf6146 100644
--- a/src/blib2to3/pgen2/tokenize.py
+++ b/src/blib2to3/pgen2/tokenize.py
@@ -487,7 +487,7 @@ def _split_fstring_start_and_middle(token: str) -> Tuple[str, str]:
 
 
 class FStringState:
-    def __init__(self):
+    def __init__(self) -> None:
         self.stack: List[int] = []
 
     def is_in_fstring(self) -> bool:
@@ -496,9 +496,6 @@ def is_in_fstring(self) -> bool:
     def is_in_fstring_expression(self) -> bool:
         return bool(self.stack) and self.stack[-1] != STATE_MIDDLE
 
-    def is_in_middle(self) -> bool:
-        return bool(self.stack) and self.stack[-1] == STATE_MIDDLE
-
     def current(self) -> int:
         if not self.stack:
             return STATE_NOT_FSTRING