Looks like casting flash from just underneath the valley pan...webbing between lifter areas. If no other metal came out...wouldn't worry. I would however take a rare earth magnet and move it around outside of pan....or a new extendable probe with magnet and move to around inside of pan. I'd do that before pulling pan..oh..and id open up oil filter. And before I pulled the pan...id see if I could rent, borrow or buy a flexible camera to peek inside..I bought one for $85.