What Causes A Band Of A Crusty Dry Red/brown Appearance After Circumcision?

Question : Hello,
I was circumcised just over a week ago and since then a central horizontal band of the surface of the glans has taken on a crusty dry red/brown appearance, but the corona and the tip near the meatus look normal pale pink. I suspect this might have been a standing issue that wasn't so apparent while I had a foreskin, when the glans was in a moist condition. I have been applying Vaseline to the glans, which was the general advice given for post-operative treatment, but don't know if this is the right course of action in this situation. What else should I do please?
Other details:
I am 68 years old; 72" tall; 11 stone in weight; Body mass index - 20.9.
The only medical issue I am having to deal with is for a large prostate gland (or BPH) and this is being treated with medication: Tamsulosin and Finasteride.

Dear Dr Asmeet XXXXXXX Sawhney,

Thank you for your assessment of 15.5.18 of my condition and I am writing to let you know the outcome. I suspect it was a touch of Zoon's balanitis, the complaint of which I had been suffering badly from back in March/April, which prompted me to go for a circumcision on 5th May. The patch of reddish/brown crust, which I described, formed shortly after the surgery and I applied Vaseline daily thereafter. But later in the day after I contacted healthcaremagic, I noticed that the edges of the patch were lifting and also, curiously, the patch had slightly changed position from horizontal to diagonal, whilst still in tact!? After a subsequent soak in bath of hot salt water for 20 minutes, the patch suddenly and spontaneously lifted off and floated to the water surface, leaving the skin beneath the same as the rest of the glans.

So I conclude this was a last 'post-op kick' from balanitis ... but I've made sure it doesn't happen again.

Regards,

XXXX