Worth-ship

"If you make an altar of stones for me, do not build it with dressed stones, for you will defile it if you use a tool on it."

...if you make an altar...

an altar is a structure, a purpose built structure for making offerings to a being.
some people make altar's to animals, or to celebrities. We make altar's to our God, creator of heaven and earth.

I will take the initiative to suggest that this phrase might be rendered "when you make an altar". When is not a correct translation, but 'when', i feel, emphasises the fact that we will be erecting such a structure, as opposed to 'if' you ever make an altar.

...do not build it with dressed stones, for you will defile it if you use a tool on it.

dressed stones. stones that have been crafted. in the NT paul refers to individual members of God's church as living stones. So when we build an altar to God with stones, we build an altar with ourselves, with our lives, our actions, our souls.
It would be easy at this point to take the second part literally and suggest that those who have tattoo's or those who have wounded themselves cannot offer themselves to God as an offering. However to do this requires mixing the metaphorical with the literal and I do not believe that this is a correct rendering of the text.
Instead I suggest that 'using a tool' implies the works of our hands. If we try to make ourselves a more worthy sacrifice by deeds or actions or creations. God is calling us here to offer ourselves to him naked and unashamed. Paul says 'boldly approach the throne of grace'.
When Adam & Eve were in the garden of eden pre-fall they were naked and unashamed, so must we commune with God, not hiding anything but 'presenting our bodies as a living sacrifice, holy and acceptable'.
For Christ has made us righteous, or in right standing with God, Christ has sanctified us, and Christ has redeemed us; so that we can now approach boldly without fear of destruction from God's holy presence.

But we must approach not with the works of our hands, not trying to be something, or trying to bring something that we have made, but simply bringing ourselves.

When we sing worship songs or write worship songs, we do not offer those songs to God as a sacrifice, we offer ourselves.

At this point you can start to see a frame of mind that would suggest, why then should we be creative if God does not desire us to offer our creation to Him. God delights in our creativity, but he wants us to bring ourselves to the altar, not the things we have created. The mere fact that we create is part of offering ourselves naked and unashamed before the Lord.