TLDR: is it contagious? See pics below

This morning My 6 y/o said his finger hurt. I asked what happened. He said he didn’t know. I took a look at it and asked if he scratched it. He said yes, and when I scratch it, it hurts. I washed his hands w soap. Put some Benadryl cream and bandaged it and sent him to school. I put the bandaid so he wouldnt scratch it some more.

I asked to see it afterschool and he said the bandaid fell off. The tiny bumps are still there but it looks slightly better.

I’m just worried it’s contagious. Dd is going thru OIT so I have so much anxiety about her catching stuff. I checked his entire body and nothing. Just that left index finger.