Leave the old spikes in place a spike head looks better than a hole in the gutter.
Gutter spikes not holding in facia.
Avoid using gutter spikes that don t have threading since they can easily pull out from your fascia board and cause the gutters to sag again.
Just hook the bracket under the front lip of the gutter and then screw the other side of the bracket to the fascia.
If you have water getting behind the gutter in any way that will start to soften and eventually rot the wood.
Gutter spikes drive through the gutter and into the fascia board that is behind the gutter.
Once this happens the wood will no longer be able to support the gutter and the gutter will either start to pull loose or sag in that area.
Replacing them with steel gutter screws and rigid plastic ferrules provides a more secure alternative and will prevent them from pulling loose or sagging.
Then use a cordless drill to drive the screw into a new hole in the fascia board.