I forgot my iphone's passcode. Is there any way to get into it without the code?

I can't remember my phone's passcode at all, and it won't let me use my thumbprint. I've been locked out for days now!

Yes. Put the iPhone in DFU mode and restore in iTunes. This will delete everything off of the phone, but you'll be able to get in. Just make sure you remember your iCloud account if you have Find My iPhone enabled.

No, there's no way to get back into it without the passcode. Even Apple doesn't know your passcode. The only thing you can do is completely reset the phone, and then you lose everything stored on it.