Painful pip after switching testosterone source

I have insane pip after switching testosterone source. My other source was pharma and used grapeseed oil and new source is UGL using benzyl benzoate. It injects way faster but I have a huge bump and pain that lasts around a week. Is it the oil inside that does that, is it the quality ? I’m trying to change back to a source that has grapeseed oil but I have a couple of vial to use and was wondering if you had any trick to make it better? Thanks