To address this thoroughly original objective...(!)
I agree with Gareth in the comments - this seems to me like a legitimate and well-formed &lit cryptic clue...
The wordplay uses the word 'primarily' to indicate one should take the leading letters of the words that follow - these aren't temporary transformations of one's skin - which yields the 7-letter answer TATTOOS. 'Primarily' is a common indicator for cryptic wordplay of this type and can be found in many online lists of 'letter selection indicators' (which is usually a good sign).
There is no separate definition in the clue - the entire clue doubles as its own definition, which is the very definition of an '&lit' cryptic clue. The use of an exclamation mark at the end of the clue is a common device to indicate that the clue is indeed an &lit.
So from a cryptic clue construction perspective everything seems in order. However, there is another consideration you might like to bear in mind here, and it's important to ask - although it may not immediately be obvious why - is this going to be your first one?
If this will be your first tattoo, and the creative intention here is that the clue seems doubly clever because its answer alludes to itself, then beware that you will be alluding to a singular tattoo with a plural solution word!
It's usually an important consideration when designing a cryptic clue to make sure that the singular/plural status of the definition matches the singular/plural status of the solution - so (to think up a random example) 'Chimp, perhaps, mashed pea (3)' would be an acceptable clue for APE, but 'Chimp, perhaps, mashed peas (4)' would not be acceptable for APES, since 'chimp, perhaps' is singular while 'apes' is plural - a clash. While in your suggested clue the definition and wordplay match perfectly (the use of 'these' and 'transformations' in the wordplay implies a plural answer), the additional third layer of complexity that this is to form the basis of an actual tattoo (singular) means that a particularly nitpicky cryptic clue enthusiast may feel that it's a case of "very, very close, but no cigar"...
If you can cope with that, fine (and if it's not your first tattoo then this point can safely be ignored, as you can consider your clue a 'caption' of sorts to the whole collection of your body art!). But just in case this does give you the slightest hint of doubt, how about a slight tweak, in which you alter the clue a little to generate the singular answer TATTOO? For instance:
Primarily, this artwork tints the outermost organ! (6)
And if you ever did get more tats, something like this would still work self-referentially among the rest, standing the test of time.
That's a thought to obsess over!