My rats tend to get lumps on their neck occasionally which are always abscesses that pop on their own. The reason for the lumps are unknown but I am trying to improve the cleanliness of their cage. About a month ago, Yoda formed an abscess under his chin and it opened just before I went on holiday. I asked my dad to wipe the area with saline solution until it healed as I usually do, and it was healed by the time I came back. A few days ago, I felt a tiny bump on his neck sort of like a small pimple or wart. I decided to just see whether it developed or not and today I saw that it was quite a flat but larger lump and I'm wondering if it didn't heal properly. I think it's worth giving him some antibiotics since I have lots left. Is there anything else I could do?