It’s certainly lucky that you’re getting this mawile as a hatchling, rather than as a pokémon who was raised in the aforementioned hoarding situation. Because of this, you won’t necessarily have to help it through any resulting trauma.
That having been said, though, you’ll of course want to follow the instructions Nurse Joy will give you on infant mawile care. Once it’s grown enough to be weaned and to live on its own, basic care should be fairly easy. It will need a soft bed and a room indoors, preferably one that’s a little on the cooler side if you live in warmer climates or climates in which it gets hot during the summer. Feed it a varied diet (mawile are omnivores) consisting of mostly berries, vegetables, and grains, with leaner meats for protein. Mawile also can be trained to use the toilet, although they typically use a litterbox (as with many fairy-types), and when grooming, be sure to polish your mawile’s horns with standard steel-type polish (as with all steel-types).
About the only differences between caring for mawile and caring for most other pokémon lies in, well, its jaws and nature. First and foremost, as a part-fairy, it’s important to be on guard around it at all times. It’s not as mischievous as, say, a clefairy or a mimikyu, but it’s still well known for deception and trickery. Never hand-feed it, in other words. And make sure you place everything that can fit in its horns out of reach.
As for the second part of that equation, its horns. Those must be well-maintained, and you do this by not only polishing the outside but also brushing the inside as you would teeth. Keep your mawile calm through the process, as challenging as it may be to do so. You may wish to distract it with music, a movie, or toys when it’s young, but it’s also possible to train it to consider such grooming to be pleasurable. That should take care of unintentional bites, but when it comes to intentional, you’ll want to wear heavy gloves at first as you work with your mawile’s jaws. Of course, it’s also important to teach it that biting you would hurt more than just a little bit, but when it’s young, it may be difficult to wean it off mischievous tendencies. Just have patience and reward your mawile whenever it displays positive behavior (sitting still while not biting you), and the job will eventually get easier as time goes on.
Best of luck, anonymous!
The Pokédex According to Bill 