Isaiah 50:4 The Lord GOD hath given me the tongue of the learned, that I should know how to speak a word in season to him that is weary: he wakeneth morning by morning, he wakeneth mine ear to hear as the learned.5 The Lord GOD hath opened mine ear, and I was not rebellious, neither turned away back. 6 I gave my back to the smiters, and my cheeks to them that plucked off the hair: I hid not my face from shame and spitting.
This is a prophecy of the experiences of Jesus Christ.
Tongue of the learned
John 7:15 And the Jews marvelled, saying, How knoweth this man letters, having never learned?
Opened mine ear
We find similar words in Psalm 40
Psalms 40:6 Sacrifice and offering thou didst not desire; mine ears hast thou opened: burnt offering and sin offering hast thou not required. 7 Then said I, Lo, I come: in the volume of the book it is written of me, 8 I delight to do thy will, O my God: yea, thy law is within my heart.
We understand from Hebrews 10 that this refers to Christ
Hebrews 10:5 Wherefore when he cometh into the world, he saith, Sacrifice and offering thou wouldest not, but a body hast thou prepared me: 6 In burnt offerings and sacrifices for sin thou hast had no pleasure. 7 Then said I, Lo, I come (in the volume of the book it is written of me,) to do thy will, O God. 8 Above when he said, Sacrifice and offering and burnt offerings and offering for sin thou wouldest not, neither hadst pleasure therein; which are offered by the law; 9 Then said he, Lo, I come to do thy will, O God. He taketh away the first, that he may establish the second. 10 By the which will we are sanctified through the offering of the body of Jesus Christ once for all.
Gave my back to the smiters
Luke 18:33 And they shall scourge him, and put him to death: and the third day he shall rise again.
Shame and spitting
Matthew 26:67 Then did they spit in his face, and buffeted him; and others smote him with the palms of their hands,
There is no record of Jesus having his facial hair plucked but that may be an unrecorded part of his treatment.
Clearly it is a prophecy of Christ’s experiences.
Isaiah is not speaking of his own experiences.
I hope you find this helpful.