Tazio, looking at the OP's pic of his leg, the the bull's eye rash is clearly seen where bite was, so as has almost certainly been confirmed by his doc, it's Lyme disease.
Last time I had a tick was summer last year, never felt it bite, could barely see it as it was tiny. Looked like a tiny bit of dirt. We'd been canoeing down at Lochore Meadows. From carpark to water was less than 5 meters, we landed on one of islands for a wee look so hard to know where it hitched a lift. Was checking my leg every day for a couple of weeks for signs of the rash. All OK though. I'm now paranoid about checking for ticks where I'm likely to get bitten.
Had to remove tick from one of our cats recently, luckily it was on it's ear so visible.
Looking back now he's cut it down to one pic it is indeed very clear. Ticks really are evil little buggers.