You just compiled your kernel - it is not an updated kernel but it is hopefully now configured to your system rather than the "standard" kernel supplied with the slack install disk.
You now have plenty of experience to try upgrading to a newer kernel. I'm fine with the one I've got (2.4.20), it works fine for me
I may join you in upgrading soon though.
edit: sorry Mara! it could be that, if you did "make install" then ran "lilo" as root you should be ok though.