Hello! thank you for your query. Cellulitis is a type of inflammation of the skin that is usually from an acute infection. It usually follows from a cut, bite, laceration or punctured wound in the skin although the entry is not obvious, this may be cause by normal flora(usual bacteria/normal bacteria found in the body) in the skin that enters the dermis(a deeper layer of the skin) through the given entry above(cuts, laceration, bite, wound) and multiply to cause cellulitis. In rare cases, cellulitis may result from distant seeding(movement) of an organism from a distant infection especially when you are immunocompromised (low immune system making you susceptible to infections). The part that is infected may manifest as redness, pain, swelling and warmth. Is the lump found on the cellulitis or is distant? if it is distant and is just a lump with no signs of swelling , then it may be a lymph node and yes it will go away with antibiotics treatment. If the lump is accompanied by swelling and pain then it may be a beginning folliculitis(another type of skin infection) that may eventually lead to cellulitis, it is better to have it checked as these should be assessed clinically for better treatment and diagnosis. I hope this helps, your feedback is greatly appreciated. Thank you!