My 21 months old fell down the stairs

So my kid fell down the wooden stairs and got a big bump in his head with a tiny scratch in the middle. He started crying at the second and fell asleep 2 min after on me. He was also due for a nap so I don’t know if it’s related. We have been in emergency so often these past days and I don’t know if this is an emergency or if I should wait until he wakes up. He is breathing fine but my heart is crushed. What should I do

Update : he is doing fine, his bump went down :) thank you for all your advices. Doctor said as long as there was a bump and not an indent it’s fine