Clean shallow 3/8" knife cut base of thumb. Next morning reddish, little puffy, slight sting.
Possible simply typical slow healing from diabetes, but it seemed interesting anyway.
Somewhere I have an OP on why semen in eyes stings so much, so consider this one part of a series.
“Let’s put semen in things and see that happens”
Ok I’m game - Toss a load into your lawnmower gas tank and get back to us.
Mods:
Ordinarily I’d call the ninja-before-sort-of-serious-reply GQ rule, but in this case I think the rules can be relaxed, so don’t note astro, OK? 
Your semen, or someone else’s?
Hmm, autoimmune angle. Mine.
Any recent loss of visual acuity?
Checked that already.
i’ll take time to answer after i fill up my lawnmower tank.
Are you sure you didn’t impregnate the wound ?
A head wound would explain Athena, then.
Why not simply normal infection? Why would you ascribe anything to the influence of semen?
Well thats why I’m asking. Did Occam whack off?
He may have done some manscaping with his razor.
Wouldn’t your natural immunities fight off the invasion just as it would if you got mustard, beer, or dirt in the cut? Doesn’t matter what it is the body fights it off. Inflammation and redness is just part of the healing process.
For all we know there’s already mustard, beer, and dirt in the cut along with the semen. In order to resolve this he’ll need a series of cuts containing the possible combinations of mustard, beer, dirt, and semen to determine if they respond differently, plus a control cut that is uncontaminated.
Probably, but he was smart enough not to whack off while holding his famous razor.
It’s not that simple when you’re diabetic. It affects EVERYTHING.
I recall from my health/sex-ed class that semen contains a fructose-rich fluid (as food for the sperm) it’s possible this allowed bacteria to grow far more rapidly than they would in a normal cut.
Just a WAG.
Leo Bloom is practicing for his new career as a מוהל (Mohel) and is still working on getting adroit at it.
I’m diabetic myself. Cuts heal slower, and we’re in grater danger of infection for a number of reasons. But once the substance is cleaned out of the cut, it’s no longer the problem. The problem is the body’s limited response, regardless if it’s a clean or previously dirty cut. Poor circulation, lower red and white blood cells, cell reaction, will be the determining factor. Clean it well. Watch it closely. Keep pressure off of it. Keep it moist with antibiotic ointment. It should heal ok.
Two thoughts, without conclusions, occasioned by OP:
A WAG–semen, like urine, is sterile (heh, irony) before it passes through the urethra (there was a long thread on the case with urine a while back). So it’s not sterile on impact.
That upon drying it does its stuff and hardens (another heh), thus propping the wound open, which can’t be good.
ETA:dstarfire mentions fructose rich. Good for bugs.