Sore after sex

I’m 28+2 and had a little more sex than usual these past few days.

After sex when my boyfriend has finished inside of me, the inside of my vagina feels so sore, almost like on fire and so achy!

My whole vulva tends to ache and feel quite swollen and within a few hours I’m back to normal, but what do we think it could be?

Anyone experienced anything similar?

Is there anything I can try to help???