"He is...a man of sorrows, and acquainted with grief...Surely He hath borne our griefs, and carried our sorrows...and [He was] afflicted...He was afflicted"
(Isa. 53:3-4,7)
Being afflicted does not mean we cannot help the afflicted. A one-armed man can still reach out a hand to a drowning man. Jesus' enemies said of Him, "He saved others; himself he cannot save."
In the worst of all afflictions our Lord helped another on to God. He didn’t allow His own infirmity to keep Him from being a blessing to others.
As to helping Himself, it is not that He couldn't, it is that He wouldn't. We're told He could've called on the Lord and God would give him twelve legions (several thousand) of angels. God has a specific will for each of His elect-- some have faith to be delivered, others, by the same faith, to not accept it, Heb. 11:32-39. Paul was Christlike in this respect.
More times than none, the Lord uses us not in spite of our shortcomings, idiosyncrasies, and failures, but rather because of. God doesn't get as much glory from our perfections as He does our imperfections. God's five ranks of laughable fools in 1 Cor.1:26-29,31 are all for His glory. "For ye see your calling, brethren, how that not many wise men after the flesh, not many mighty, not many noble, are called: But God hath chosen the foolish things of the world to confound the wise; and God hath chosen the weak things of the world to confound the things which are mighty; And base things of the world, and things which are despised, hath God chosen, yea, and things which are not, to bring to nought things that are: That no flesh should glory in his presence...That, according as it is written, He that glorieth, let him glory in the Lord."
