My cat has a yellow bump on its lip/chin. Is it a pimple or infection?

This looks like a small, localized spot of infection, sometimes referred to as a hot spot. If the infection is contained to this one area you can try to treat it at home with some topical antibiotic ointment (like Neosporin). If this does not take care of the problem, or if there are other areas like this on her skin, I would recommend having her checked out by your vet so a systemic antibiotic can be given.

Hi there and thank you for using Petco Pet Education Center, formerly Petcoach to address your concern. Based on the pictures you provided, I would recommend just monitoring this for the time being. It could be an area swollen from her hitting her chin on something or it could be an infection / pimple (acne). If it does not resolve on its own, I would recommend having Mouse examined by a veterinarian so that the most appropriate diagnostic and treatment recommendations can be made. I hope this helps! Please let me know if you have any other questions or concerns and I would be more than happy to help you further. Please take the time to mark this question as helpful or not as it helps us to improve on the quality of our answers to other pet owners. Thank you kindly!

Hello there, Thanks for the good photo. If it is a small minor wound like a pimple or scratch, it should be mostly healed within a week of forming. If its been present for longer than that or is worsening, I would be more concerned that it is the start of an infection or growth that would benefit from being seen by her veterinarian. I hope this helps. Thanks for using Petco Pet Education Center, formerly Petcoach.

This looks like a mild skin infection. Your veterinarian will be able to perform a test (skin scrape and cytology) to determine what might be causing the infection and prescribe appropriate treatment.

This is probably chin acne. ( https://vcahospitals.com/know-your-pet/chin-acne-in-cats ) You can try these medicated pads on the affected areas once a day. If it doesn't seem to help within a week or so of treatment then I suggest you take him to the vet for an exam. ( https://www.amazon.co.uk/Douxo-recommended-antibacterial-antifungal-wipes/dp/B07JKTKZZG/ref=sr_1_1?keywords=duoxo+pyo+pads&qid=1581780497&s=pet-supplies&sr=1-1-catcorr )

This could be a pustule which is a local bacterial infection or even a small cyst. If it is just one it may go away on its own. But if there are multiple, this one becomes larger or seems painful your cat may need medication from your veterinarian.

It is possible this may be related to inflammation such as from a flea allergy so i recommend treating with a flea medication such as comfortis as soon as possible. Prescription antiinflammatory medications from your vet may also be required