Researching the purpose of tattoos, too. I googled "the purpose of tattoos" and checked out some of the sites. They didn't give a full answer, but they shed some light on it. Hope it helps.
Psalm 22:16 says, "They pierced My hands and my feet." It's referring to the nail piercings that Jesus received when He hung on the cross.
Isaiah 53:5 says, "With His stripes we are healed." Through His suffering, our hurting lives can be changed! I pray you know this personally. God bless you!