Interestingly, the only time the word medals is mentioned in the ARTICLE 1 - SACRAMENTALS of the CCC is under the Popular Piety section,
(italic is mine)
1674 Besides sacramental liturgy and sacramentals, catechesis must
take into account the forms of piety and popular devotions among the
faithful. The religious sense of the Christian people has always found
expression in various forms of piety surrounding the Church's
sacramental life, such as the veneration of relics, visits to
sanctuaries, pilgrimages, processions, the stations of the cross,
religious dances, the rosary, medals, etc.
This paragraph is giving the impression that not even medals can be considered sacramentals!
There is also an etc in the end of the paragraph sufficiently ambiguous.
Better consult the Compendium of the CCC
(italic is mine)
351. What are the sacramentals?
These are sacred signs instituted by the Church to sanctify different
circumstances of life. They include a prayer accompanied by the sign
of the cross and other signs. Among the sacramentals which occupy an
important place are: blessings, which are the praise of God and a
prayer to obtain his gifts, the consecration of persons and the
dedication of things for the worship of God.
Can a tattoo be considered a thing? Don't know.
Better ask a "tattooed millennial priest":
Can tattoos be sacramentals? [Article from the CNA]
“Sacramentals, used well, keep us close to the grace of Christ given
to us in the seven sacraments, and receive their graces by the
authority that Christ gives his bride, the Church, when she asks for
his help. When the Church asks Christ for graces, He never refuses his
“This means that sacramentals only work when they are done according
to the rules of the Church. If we want to ask Christ for these graces,
we need to make sure we do so authentically as the Church, obediently
accepting the rules she sets down. It's clear in Canon Law that the
Apostolic See alone has the authority to establish sacramentals and
define the criteria for their use [c. 1167],”
"However, he added, it is possible that tattoos could be
“sacramentals” in a broader sense of the word."
which means in a strict sense they are not.
He keeps talking,
“A permanent image, engraved on the skin, could certainly serve as a
constant, physical reminder of our new life in Christ. The image of a
rosary, a cross, or other sacramental on our skin could lead us
frequently to pray, to desire the seven sacraments more, and to think
and act in communion with the Church,” he said.
“So, while a tattoo could not fulfill the requirements to be a proper
sacramental in itself, if used in discernment and good faith it could
certainly provide similar benefits and be helpful in the pursuit of
And here we have the confirmation that tattoos can not be considered sacramentals.
I can't confirm a tattoo can be blessed without being considered a sacramental.