can I use antibiotics that are out of date

I have a ear infection.. and I had spray off the doctor that had to be used in 21 days of opening then chucked away
On the bottom the date is 2018 that it expires but if u open it you got to chuck it away
Can I still use it? It's gone 21 days I only used it for a week as I was on holiday and forgot it! But I still have a ear infection