Have you taken your medicine today? Do you expect it to heal you instantly or do you need to take it 3 times a day until all the sickness is gone? Do you take it because you believe it will overcome your health problem? Do you have someone's authority, probably a doctor, who has told you it works?
Good news! There is another medicine that has great reviews and authority that declares it works.
In Proverbs 4:20-22, "My son, give attention to my words; incline your ear to my sayings, do not let them depart from your eyes; keep them in the midst of your heart; for they are life to those who find them and health to all their flesh." The word "health" in verse 22 has the original meaning of to heal, to cure, to act as a medicine.
Sometimes people don't get instant results of healing when they declare, "By His stripes I am healed" or the words of Isaiah that Jesus quoted in Matthew 8:16, "He Himself took our infirmities and bore our sicknesses." So they give up and say I just don;t have enough faith. Let me ask a question, do you give up if you take one pill and the sickness isn't gone? Of course not. You faithfully take the pill 3 times a day until the symptoms disappear.
So the answer is to keep taking the medicine. It is not based on whether you have enough faith, it just depends upon you continuing to take the medicine until your health is restored. Every time you declare the Word something happens in the heavens and on the earth. Death and life are in the power of the tongue. You release life. Stay with it, keep paying attention to God;s Word, keep your eyes focused on the truth, and keep treasuring that thought in the midst of your heart. Out of the abundance of the heart, the mouth speaks. You don't have to judge how much you believe or how good your faith is, just read the word, think about it, and say it. Quit debating whether the medicine works, just take it.
Whenever I start to declare God's Word and am struggling to believe it (I believe, Lord, but help my unbelief!), God is so merciful He comes through for me so much more than I could have expected or imagined. He is so good. Do what is in your power to declare it and believe it. Say the verse out loud so your own ears hear it (faith comes by hearing), and take your medicine regularly--3 times a day--until you see the salvation of God.