There are better fingerboard sealants. You are risking introducing mold into the grain of your 'board. Clean your hands, wrap a bit of cloth tightly around the backs of the strings and slide to fully clean before and after playing, and learn proper fretting technique and you'll never need to lube your fingers. Leave the olive oil in the kitchen and the snake oil on the shelf at the guitar store.
Regardless of your motivation, take your poor guitar to your nearest luthier and have them undo the damage you've done and apply the proper moisturizer/sealant. Two thimbles of tung oil is cheaper than salad dressing and a fingerboard replacement. They'll likely not charge you more than twenty dollars. Ask some fretless bassists, cellists, etc. if they lube their fingers. It's all about the angle at which you have your fingers and the tiny lateral finger muscles holding the tips firmly in line. Callouses are not necessary, most of the best don't have them. Clean strings are slippery enough. If you're hanging up, they're not clean. Best wishes!
No, but that's a good idea. I almost bought a guitar a few months ago, but I remembered how it callused my fingers before.