Hi. Some deodorants can indirectly cause lumps in the armpit by causing irritation and inflammation of the skin. The inflamed skin may lead to secondary infection of the hair follicles in the armpit, resulting in folliculitis, which manifests as lumps under the arm. Lymph nodes around the area may also become swollen because of the infection. This also may appear as lumps.
it is possible if you are allergic product and the deodorant can get clogged into your pores that can affect the hair follicles creating bacteria. Afterwards proteins and white blood cells from your body try to form to block bacteria but it grows into a lumps
if you are having multiple lumps it could be HS
if it is not painful than it could be lymphoma
sure this would help