No it is not possible from just messing around. Not unless he came on his finger and put it up your vagina would there ever be a chance.
You cannot get pregnant from being fingered. You have to come in contact with sperm. If that was on his fingers, then there is always a possibility, but it would be unlikely.
If there was no sexual penertartion with a penis there is little to no possibility of getting pregnant.
The seman has to enter the vagina in order for you to become pregnant.