What’s bitten dp?! Pic included!!

[usedandabusedx1000]

He’s been itching his shoulder and now this....I’ve no idea what it could be so thought I’d ask the masses?

Ouch. Where would he have picked up the thing that bit him? It doesn't look like a tick bite but do keep an eye on it. Might be worth drawing a ring round it (where the swelling stops) so you can see easily if it's getting bigger or smaller.

He’s been home all day which is what worry’s me

Is it any bigger today, OP?

It could be a spider bite.
Or
He could be Scaramanga.