Tattoos were forbidden under the Old Covenant that God made with Israel at Sinai.
Leviticus 19:28 Ye shall not make any cuttings in your flesh for the dead, nor print any marks upon you: I am the LORD.
Israel failed to keep the Covenant and God promised a New Covenant.
Jeremiah 31:31-34 Behold, the days come, saith the LORD, that I will make a new covenant with the house of Israel, and with the house of Judah: 32 Not according to the covenant that I made with their fathers in the day that I took them by the hand to bring them out of the land of Egypt; which my covenant they brake, although I was an husband unto them, saith the LORD: 33 But this shall be the covenant that I will make with the house of Israel; After those days, saith the LORD, I will put my law in their inward parts, and write it in their hearts; and will be their God, and they shall be my people. 34 And they shall teach no more every man his neighbour, and every man his brother, saying, Know the LORD: for they shall all know me, from the least of them unto the greatest of them, saith the LORD: for I will forgive their iniquity, and I will remember their sin no more.
Hebrews 8:8 For finding fault with them, he saith, Behold, the days come, saith the Lord, when I will make a new covenant with the house of Israel and with the house of Judah:
The New Covenant supersedes the Old
Hebrews 8:13 In that he saith, A new covenant, he hath made the first old. Now that which decayeth and waxeth old is ready to vanish away.
Jesus Christ is the mediator of the New Covenant.
Hebrews 12:24 And to Jesus the mediator of the new covenant, and to the blood of sprinkling, that speaketh better things than that of Abel.
The New Covenant requires those who believe the gospel and are baptised into Christ for the remission of past sins, to live by the commandments of Jesus Christ.
John 15:13 Greater love hath no man than this, that a man lay down his life for his friends. 14 Ye are my friends, if ye do whatsoever I command you.
Luke 6:46 And why call ye me, Lord, Lord, and do not the things which I say?
John 14:21 He that hath my commandments, and keepeth them, he it is that loveth me…
Jesus Christ gives no commandment concerning tattoos. Tattoos will not prevent entry into the kingdom of God.
I hope you find this helpful.