I got a summons to go to court for lying to a law enforcement officer, I am currently on proabtion< what could happen? My probation officer does not know yet.what should I do?

You now have two violations of PO

1. getting a summons

2. not telling the PO

Most likely the PO will view number 2 as a much more serious issue.

You need to tell the PO before he finds out on his own.