Neither one is 'correct' they are both used in common parlance.
A bump is a lump like, for example, a bump on your skin or a bump in a road.
LUMP
Bump Chump Pump Lump
The English words lump and bump mean roughly the same as the Tagalog word bukol.
A lump usually refers to a mass or swelling beneath the skin, commonly due to tissue growth or inflammation. On the other hand, a bump is a raised area on the skin that can be caused by various factors such as injury or insect bites. Essentially, a lump is a more generalized term for any abnormal growth or swelling, while a bump is more specific to a raised area on the skin.
Like a hairy lump
Depends on the nature of the lump/bump. Might be acne (yes, it does happen there), or it could be something much, much, worse, and destined to cause you a whole lot of suffering.
It is Knock
A person with a bump could be described as having a swelling or lump on their body. It would be best to refer to them based on the specific location or cause of the bump if known.
it may be a serois medical conditiion, ask a vet. is the rat old? is the bump big? is the lump swollen? is the bump on a patch of thin skin? where has your rat been? is the bump smooth or scaly or something else?
Bump, clump, (a) hump, slump, grump, lump,
bump, lump, clump, rump, dump, hump