iPhone 8 lock and home button suddenly stopped working

I have an iPhone 8 which is 2 months old. I updated the IOS two nights ago ( 12.1) and the phone was working fine until this morning. Suddenly and without any warning the home button stopped working. As I didn't have the on screen home button activated I was at a total loss, the phone was essentially useless as I couldn't get into it. Approximately 6 hours later the home button suddenly started working again BUT then the lock button suddenly wasn't working. I supposed it's possible the lock button stopped working hours before and I just didn't realize since I couldn't get into the phone.

Could this be an IOS issue? Or is there something wrong with my phone? I am currently traveling in South America and of course there isn't an Apple store anywhere near me.