system
Given the following post, respond as if you're commenting on Reddit:
human
After putting down a hot plate, why does the pain persist, is it because of swelling?

I just held a pretty hot plate of food, but after putting it down, my fingers are still stinging a little, with slight swelling.

I get that because it's hot, the heat receptors in my fingers have sent a signal to my brain: is it correct to say that my brain then processes this and 'says' that it is dangerous, so I feel pain because I'm being made to stop holding the hot plate?

Are there different receptors for 'okay temperatures' and 'not okay' like there are for cold and hot relative to our body temperatures? Do these temperatures change? Like chefs have 'abestos hands' is this a receptor/nerve thing (one post suggested the nerve endings here may have been damaged), or is it really thickened skin, or is this a mental thing?

Then, after I put down the plate, I notice a little swelling on some of my fingers. Apart from the temperature differences across the bottom of the plate, does acclimatisation to the high temperatures also impact the degree to which I experience swelling? Is this swelling the reason I feel slight stinging even when I do not type, or is it residual heat?

Lastly, if it's not residual heat, could you also explain why without the hot plate as the stimulus, we feel pain? eg. not just with a hot plate, but when we accidentally whack our toe into a table leg, and quickly jump off, why does our toe throb even after the impact has ended like a couple of seconds before? -> has the pain been extended by our brain to make us remember, or is the signal continuously coming from our sensory neurones in our toe firing like crazy? -> I've done a quick reddit search and but only found the gympie gympie plant post about prolonged pain.

Sorry for the multiple questions, thank you very much!
(re-post with question mark in title)
gpt
There are basically 2 types of temperature receptors in our skin. One detects hot temperature and one detects cold.
But the associated pain is not due to response from temperature receptors of the skin. Pain is carried by a different set of receptors and nerves. The damage to the tissue (skin cells) causes them to release certain chemicals in their surroundings. Substance P and bradykinin are most common of these chemicals. These chemicals cause the stimulus of pain.
The swelling in the area occurs due to damage to capillaries (these are very small blood vessels) which then becomes leaky and the plasma part of the blood leaks out in between the skin cells.
Any area of inflammation would show features of 1. rubor ( redness) 2. dolor ( pain) 3. calor ( increase in the temperature of that area due to dilatation of blood vessel) and 4. Tumor (swelling)
The pain you experience would last till those chemicals (which came out of the damaged cell) are cleared from that area.

Upon repeated exposure to a painful stimulus regularly such as playing the guitar callouses may develope on the finger tips which is basically dead skin cells. But these dead skin cells prevent the activation of pain sensing nerve fibres.
However, if the pain stimulus is more traumatic where a larger number of cells are damaged, such as  burns on the skin, repeatedly giving the same stimulus would not cause lesser pain.
But in case where the burns are deep enough to damage the nerve fibres, that area of skin may turn into a scar tissue and would have lesser sensations.

If you whack your toe, the pain sensing nerves of the area get activated, and send signals to the brain. The persistence of pain is due to those pain chemicals which were released by the damaged cell.