The light used in taking a photograph makes a big difference in whether healed or healing bruises or scratches can be seen.
Mug shots are not usually taken by a forensic photographer. They are usually taken under flat white light (and quite a bit of light).
Here's a book on how lighting techniques affect the ability of forensic examiners to see scratches, bruises or other less visible injuries:
Forensic photography plays a vitally important part in the investigation of crime and the subsequent administration of justice. Written by a practitioner with many years professional experience, this book provides an overview of the most common forensic photography techniques in use today for...
www.google.com
P. 226 gives a very interesting example of a healing wound that was virtually invisible. First image is reference (ordinary) lighting. The others are done by a forensic photographer which, I will bet a whole box of donuts, is what they did with BCK, probably or possibly before his mug shot.
And they will likely do the photography again in Idaho. Notice how the technique called "reflective UV" gives good results of wound shape even months later, when to ordinary photography the wound looks healed. Reflective UV is used in anthropological digs and to study marks on old bones as well (as long as some even more sensitive techniques that can only be used on the deceased). At any rate, we have a reflective UV light at my public college's anthro lab (no criminology program; not that many people going into forensics; not all that expensive).
So, my suggestion is to NOT use mug shots as your forensic evidence as a websleuth. Keep in mind that there are forensic investigators with techniques that can reveal convincingly to a jury that the defendant had past wounds.
As for wound healing times, I'll try and put something together soon. I got a good scratch 12 hours ago, and I'm way older than BCK, but I bet my ordinary light photos will not show it in 10 days. Maybe less.