Bitey Face going too far?

Hi all, I have a 14 week old male puppy that loves playing bitey face with my older, nearly 7 year old female dog. They get on very well all things considered. When they are playing however my puppy really latches onto my dogs ears and legs and really bites down hard. My dog does not seem to correct him, she kind of just sits there and sometimes yelps.
Do I need to intervene at this point? Older dog is incredibly well rounded and patient but puppy has now drawn blood chewing on dogs legs and she just stands there.
Any advice is truly appreciated, thanks.