Yes it is normal for the Vulva to swell when your girl is in heat:
However, it should not be red, irritated or painful to her.
Some dogs get vaginitis:
You should see a vet if she has symptoms of that.
Otherwise she should be fine.
Warmest best wishes,
You are very welcome. It is my pleasure to help someone as lovely as you and your sweet baby.
I will always be here for both of you.
Thank you for your accept! Sending as an IR so you are not charged again!