Skin upsets - not sure if caused by skin contact or diet

Our Una seems to be a lassie with issues, we discovered Una had demodex when she first joined us and got that sorted. During this winter the wee soul had dandruff so we've been adding coconut oil to her kibble (Eden) and giving Una tuna or sardines once a week.

Now Una is smart but her enthusiasm overrides her smarts, which results in our lass charging through brambles or nettles. Una is learning where she can charge and where she needs to lightly tread but her skin is suffering. At the moment we can't tell if it is because of skin contact, like with the longer grass/nettles or something in her diet. The vet has put Una on twice weekly showers with Virbac Microbex, which she's good with (as long as there's a chicken wing to chew during the 10 minute wait for the stuff to kick in), but I'm wondering if we'll end up with some cream to use and there's my problem.

Una is very high alert and not confident, if she sees us looking at her with any sort of intent, she'll go into full avoidance mode. I can put her in the car doggy seatbelt to hold her in one place which I've done with a tick but I'd rather not do that and let it be her choice to let me put cream on her or remove the tick. How on earth can I do this or am I expecting far too much from Una? She's so scared of everything but has came on leaps and bounds these past few months and I'd hate to make her feel helpless and give her reason to be wary of me. What do you think, are there any approaches I can take to get her feeling happy about cream being rubbed into her chest and armpits?

(sorry for the ramble )

We had the same issue with my Flo, if she saw her flea treatment she was off!! Now this might seem odd but I started to show her the tube and let her sniff it whilst giving her gently reassuring strokes. After about the third time I showed her the tube and indicated where the contents go and she stood there and allowed me to do it.

Ok so there was also some food bribery afterwards but she got the idea that actually, I'm gonna get a treat here.

We are now at the point where she will go outside willingly and wait for it to be applied so that she can shake and then gets the treat

Oh that sounds good Ian, thanks! I've got an empty advocate tube so will clean that out and give it a go. I know Una may not enjoy it but I'd so like it to be her choice to put up with it for treats or something than it be forced upon her

Might take a while Ange but it worked for us, we know it doesn't hurt but they don't and I think they just kinda get worked up about it. If you can show it isn't anything to fret about then perhaps things will be better.

I actually think they are smarter than we give credit sometimes

That's it exactly - Una gets herself worried and gets into "nope, nope, nope" mode.