Can you upload a photo(s) of this pointy lump to our conversation? You can use the paperclip icon in the toolbar above your message box (if you can see the icon) or you can use an external app such as dropbox.com/ I can be more accurate for you if I can see what you're seeing. My initial thought was a cutaneous horn.
I understand. It's much too dark a photo to be diagnostic. Cutaneous horns can vary in appearance but all are circumscribed, conical or cylindrical masses of keratin that may originate from underlying actinic keratosis, squamous cell carcinoma, papilloma, or a diated pore. They're benign and of little consequence and can be easily excised if my patient or caretaker is bothered by it. Please see here for images of cutaneous horns in cats and let me know if you think Lily's lump indicates a horn: https://www.google.com/search?q=cutaneous+horn+cat+image&tbm=isch&imgil=6LKb-a02InX9CM%253A%253BXz73X9CjP89GDM%253Bhttp%25253A%25252F%25252Fvetbook.org%25252Fwiki%25252Fcat%25252Findex.php%25253Ftitle%2525253DCutaneous_horn&source=iu&pf=m&fir=6LKb-a02InX9CM%253A%252CXz73X9CjP89GDM%252C_&usg=__FW7cjIhbrBs2mbXbbp3wxLlajGA%3D&biw=1920&bih=955&ved=0ahUKEwiksMjUvJHNAhUXQFIKHROkClYQyjcINg&ei=v2lUV-TUDZeAyQKTyKqwBQ#imgrc=6LKb-a02InX9CM%3A
I wouldn't expect a horn to scab unless it had just poked through the skin and the skin is trying to heal over it. I don't know the significance of it being dark; I regret that I'm constrained from here to be more accurate for you. In general, any skin lesion that enlarges at an alarming rate, bothers my patient or caretaker, and/or ulcerates/bleeds should be excised. At that point, a vet can then advise if biopsy is indicated or not. Biopsy would be necessary for a definitive diagnosis but a definitive diagnosis isn't necessarily important when surgical resection is complete.
Please continue our conversation if you wish.
Doubling in size within a month would alarm me. There's no urgency here. A young cat is very unlikely to develop anything so serious that would preclude a few weeks of "watchful waiting".
You're quite welcome. Thank you for your kind accept. I appreciate it. I can't set a follow-up in this venue so please return to our conversation - even after rating - with an update at your convenience.