According to the Catholic Church, can a tattoo be considered a sacramental? According to the Catholic Church, can a tattoo be considered a sacramental?

I have a friend who is thinking about getting a tattoo on each shoulder, containing the image of the Medal of St. Benedict. There are several different blessings for this medal now. Any priest may bless the Medal of St. Benedict and some blessings have the word image in lieu of the word medal.

If a priest were to bless this image would it be considered a sacrament, according to the Catholic Church. 

Although I am bring up the case of the Medal of St. Benedict, any other image in use in this question could hold also.

In the case of lack of official Catholic 
Church teachings on this subject could a priest simply bless such holy images? Is there any Church prohibitions against this?

Are priests allowed to bless tattoos? After all there are also blessings for people in the Rituale Romanum!

Here follows the image of the  Medal of St. Benedict that my friend is considering.



St. Benedict Medal
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)


  Popular piety
  
  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?
  
  1667-1672 
  1677-1678 
  
  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
  bride,”


and   


  “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],”


and


  "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.


and finally,


  “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
  holiness.”


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.