my kid locked my iphone

If your iPhone has iOS 15.2 or later installed, check out this link→How to reset your iPhone, iPad, or iPod touch when you forgot your passcode - Apple Support. Otherwise:

See this Apple support link→If you forgot the passcode on your iPhone, or your iPhone is disabled - Apple Support

Or watch this companion video ⬇️

After restoring the phone using one of the methods above you can restore your most recent backup.

If you forgot your iPhone passcode - Apple Support

That is correct, at this point you need to restore your phone. Follow the instructions that sberman provided you.

Too many failed log on attempts will cause the phone to lock. If the little one could read, they would have seen a warning message that repeated wrong passcode entries would result in the phone being locked up.