If you get your record expunged in Pennsylvania, nothing should show up on your record. Once an expungement is granted, the expungement order, which per Pennsylvania law would require those records to be destroyed, it would be served upon the apical law enforcement, government, and court agencies, be the Magisterial District Court, the arresting police department, for example, the District Attorney's Office, the Court of Common Pleas, where the expungement would take place, or where the case took place if it was not resolved at the District Court would, in a sense self-serve itself.
The Pennsylvania State Police would be served with an expungement order. The Administrative Office of Pennsylvania Courts would also be served the AOPC. The Pennsylvania State Police would in turn forward a copy of the expungement order to the FBI. All those Pennsylvania agencies, law enforcement, government, and court and otherwise would be required to destroy the records. There should be nothing on the Pennsylvania State Police records. That's often the most important repository of records in Pennsylvania and where employers would go to seek a person's records.
The FBI is a federal agency. It's not bound by Pennsylvania law, but they often would do as much as they can to clean up a person's record where only a person's fingerprints may be reflected as being on file with the FBI, but no charges or anything along those lines. Everything should in essence be destroyed. An experienced Pennsylvania criminal defense attorney will help you understand the expungement process and could best attend to it for you.