some formulations of primo 200, dhb100 behave much like win/test suspension. they have a high melting point and don't really want to stay in solution, and even if not crashed there are probably microcrystals in the oil. once you inject, the oil gets resorbed with its dissolved compound, but the microcrystsals are left behind and irritate the muscle fibers every time there is motion. they also will act like miniature pellets and slow release of the compound. suspensions are exactly the same, just water instead of oil. these are not infections that need antibiotics, but major inflammation.
warming the oil before injecting to middle temp on a mug warmer (162 degrees on the one I have from Amazon) will re-dissolve any microcrystals and minimize any PIP. you can also use a baby wipe warmer and keep the oil warm all the time. diluting it with other oils (particularly EQ) helps too as others have said.
i try to avoid NSAIDs as they are rough on the kidneys, but have found naproxen/alleve works far better than ibuprofen/advil and other OTC ones for inflammatory pain - both from PIP and joint or sciatic-type symptoms that can prevent one from sleeping. Ketolorac and diclofenac are even better but script only, or can get via India pharma.