Cats can manifest some behaviors that can show us they lack something. Perhaps your cat's food bowl is empty, or she got bored, and is asking you to engage in some kind of activity with her.
If you have a young kitten, hugging your arm and biting you could be a sign of teething. You should provide your kitten with a cold wet washcloth to relieve her pain and to decrease her urge to bite you.
Your arm might also present a prey for your cat. This is perfectly natural, but, still, you shouldn’t let your cat hurt you and go too far with this game.
Your cat hugging your arm and then biting you could be their attempt to show dominance. If you let her do this often, without warning her to stop, she might understand this as a sign that she’s the boss in the house.
Hugging your arm and biting you could be a sign that your cat’s injured and in pain. If you suspect that your cat is injured, gently approach her to examine her, and consult a veterinarian.