DD - My rationale on the photo was to also record the shape of the sore. It's supremely unlikely any of these things are a uniform circle, rectangle, let alone any changes to redness/scab or whatever.
In many ways a drawing around the sore would be ideal, but as I say, personally, I'd not be keen to be applying pressure and/or ink in that area, bearing in mind it could be required over some weeks.
@AnnieBernice - Should you elect to go with the photo option, be prepared to repeat the photo session as (hopefully) your sores heal.
When I needed to go back and discuss subsequent growth on my mole, with the photographic evidence there was absolutely no suggestion of "are you sure?", as I had the photographic evidence to hand.
(The mole is no more, having had it removed.)
Annie Bernice - Did you Doc share with you what his thoughts were on the cause of your sores, or is the referral because he's not at all sure?