I have a dozen or so of those on my duranos.
Take it off see if it penetrates to the inside, if it does and If the hole is small a patch will secure it, if its bigger then a tyre boot maybe better.
If its so big that under pressure the tube can be seen...bin it.
I had 4 blow outs including a shotgun blow out when my set developed a large enough hole for the tyre to herniate through, trouble was, it was too dark to see at the time. Someone on here described how the cut had gone along or across the wires in the tyre, making it more dodgy, especially under inflation. I still don't know how to tell the difference.
Anyhow, I'd bought the tyre a week earlier and had to bin it.
A whole winter later and despite a dozen such scars and only two visits in months and months, appx 500 miles a month
Either way, as others have said, i'd swap it to the rear