Have been having this bump appearing on my labia repeatedly, at the same area. What is it?

Hey there! I've been having this bump (as per image) growing on the bottom left side of my labia repeatedly, and at the exact same spot, and it usually lasts 2-3 weeks (sometimes more), and recurs everyone 1-2 months. I can't tell if it coincides with my period. Happens regardless if I've shaved, waxed, or let the hairs grow and run wild - it has happened in every single one of these instances. It is completely skin-coloured, with no white head / black dot. It is slightly painful to applied pressure (like when i dry with a towel or wipe with toilet paper), and it is pretty tough inside (squishy on the surface but beneath feels like one of those ripe, solid pimples). I thought it was a pimple or an ingrown hair, but it doesn't seem to have a head. There never has been, any single time. As much as I've tried to squeeze it or massage it like a pimple, I can't seem to 'pop' / release it. Anyone has any idea what this could be? Thank you! And sorry for the gross, hairy, TMI pics.

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looks like cyst