Thanks very much @Mike Panic. The advice is appreciated.
Myself and my technician have discussed that perhaps my skin is a little more sensitive, coupled with the fact that that inner arm spot seems to often cause people some issues, be it during tattooing or lasering - seems to be a lot more sensitive than perhaps other parts of the body. I do wonder if movement has anything to do with it, as being inside the arm it's a little more prone to 'rubbing' throughout the day. On that note, interestingly enough the part of the tattoo that's currently most faded, and almost entirely gone in some places, is the portion nearest the armpit, which I guess experiences the most 'rubbing' through movement and from clothing. I often wonder if it's acting almost like a 'massage' to the area throughout the day, and bringing more blood/lymph movement to that spot? Or of it's literally just because that area is nearer to the trunk of the body? Who knows.
I have a treatment next weekend, so aside from the first couple of days I think I plan on pretty much leaving it alone for the duration of the healing/fading period, which will be a further 9 or 10 weeks. Plenty of exercise and healthy eating etc.
One final question: in your experience, do you find that any hyperpigmentation in the skin tends to resolve over time? From the outset the grey shading in my tattoo turned a light shade of brown. I still don't know if this was a change in colour within the ink itself (I suppose the ink could have been mixed with white which could have in turn changed colour after laser interaction?) or an increase in melanin in the skin as an inflammatory response. Those areas are very light now, but there is still a small amount of ink that needs targeting. My worry is that treating the areas again with a higher fluence (which I guess will be needed to disperse the remaining small amount of ink) could further prolong the hyperpigmentation (if that's what it is) - but I've given these areas around 8 months away from the laser now, and they don't seem to have cleared completely. I guess my goal currently is to clear all remaining ink then hope any pigmentary changes within the skin correct themselves in the months after my last treatment.
Thanks again for your help.