The arachnoid mater is one of the three meninges, the protective membranes that cover the brain and spinal cord.
Sweat trigger 4: Hot and spicy food. Spicy foods trigger the same receptors in your skin that respond to heat, which is why you have to dab your forehead and upper lip when you eat an extra-hot curry. The beer you drink with that curry could also make you sweat by widening blood vessels in your skin.
A bump inside the upper lip could indicate a canker sore or a cyst, also known as mucocele, has developed. A mucocele develops on a small salivary gland and forms a white bump on the inside of the lips that is typically painless, according to WebMD. Keep Learning.