What has bitten me? Warning: pic's included

[MyCatsAreFuckwits]

Felt an itch while out last night, located on inside calf, where seam of skinny jeans lies.
Took off jeans about 11:30 and noticed a very small bite. Took oral antihistamine and bathed area.
Small blister had developed by morning, also red and rather warm. Pen marked edge of red area at 8:30am
This is it now, 24 hours after first feeling the itch.
Any ideas of the critter that caused this?

I thought Spooner Corner would be quiet on a sunny Sunday 🌞
Warning was given in advance 😂
To be fair I'm not sure I was ready for the Spooner Corner replies 😅

Ds responds like this to a simple mosquito

Could it not be just a blister from the seam rubbing? I had a massive blister like that recently after camping and was pretty sure it was just a blister.

I also reckon horsefly, I was bitten a couple of years ago and blister was identical. Pharmacist told me to go to GP, and they prescribed antibiotics - hope it heals up swiftly for you!

Horsefly. I get this reaction too. They can get you through jeans and jodhpurs with no trouble at all!

I get this from mosquito bites, I wear insect repellent if I'm planning going somewhere known for mosquitos.

I was bitten by something yesterday on my arse. Quite surprised as I had a reasonably think pair of cropped jeans on. It's now starting to get big and red so I'm guessing there was a mosquito hiding in the toilet or something 🙄

I had this a couple of years ago. Blister finally popped but I still have a red mark on my hand where it was! Totally smooth but different colour to the rest of me forever!

I had exactly the same. Doctor guessed at spider bite (we live in central London). I needed antibiotics and had the wound packed for weeks. Go see a doctor!

OP if you know what inserts make you react like this, why are you asking? Why not just post and say “look at my blister” which is I think what you meant….

I was going to say hogweed but you seem pretty confident it’s not

I was bitten by a horsefly a couple of weeks ago. It didn't blister like that but was a massive itchy lump with a huge purple bruise around it. I'm certain it was a horsefly as they have slasher jaws and there was a long streak of blood from it. I was out walking and I live rurally. I took antihistamine and drew round it. It did look like it was spreading as it had a long red streak coming out of the bruised area. I cleaned it and used hydrocortisone cream and it settled pretty quickly. Admittedly I'd probably get that blister looked at.