Sorry to hear that,olddude. We'll a tooth can be throbbing days after it's been removed; well, not the tooth see dry sockets above. I'm not sure how the next tooth was damaged during the extraction but, if it's going dark it's dead and an abcess may be forming now. Is there a big filling in it perhaps? If you're an very old olddude, you may have worn through to the nerve by enthusiastic brushing over 90 years or so.
Doc John