The only thing I have changed was adding wood-chips behind the cool hide, in the corner (taking up less than 1/10th of the space), as I thought that perhaps it would be beneficial for shedding or otherwise? (Don't know if that assumption was far-fetched or ridiculous).
And even if, like you say, that 3 weeks without food for only a few-months-old spotted isn't something to get overly worried about; what about shedding? He hasn't shed in the two months I have had him and I don't know the date of his last shed before that. I understand that shedding is accompanied by growth and that if he hasn't been eating he's obviously not been growing, but I still don't know why he would go hungry for so long when I've been occasionally offering food in a variety of ways to see if he'd go for it.
All I know is that, while he hasn't been eating, he still moves around daily - but I can't tell if he's getting thinner (I know I should be wary of his spine becoming visible as that's indicative of a very low weight, unhealthy snake). While I take this as a good sign, there's also the fact that whenever I open the cage he tries to creep over the edge - here I'm not sure if it's because he's just curious or unhappy with his enclosure. He also moves between the cool and warm hide so I hope that means he's comfortable with the temperature.
But to be completely honest, the 3 week gap of no food (and overall eating with 2 week intervals as a young snake) is really worrying me. Sometimes, he would rest in a weird position and I have a moment of freaking out because I think he has died. I often see him drinking but he has never submerged himself in the water (as far as I'm aware), and I change the water as often as ever second day, at the latest, once every 4 days. I also want to mention the fact that he's been rubbing his face on various surfaces including the floor (is this a shedding thing or a problem, because he's been doing this since I brought him but increasingly more now).
Please help because I'm really worried that he's losing weight, becoming unhealthy, or worse, on the verge of death.