Young man will rub lard (fat from pig) into the scalp to see if he will grow more hair (from Reddit)

I feel I must comment on your experiment. Yes, doctors do inject fat into the scalp and yes doctors do inject platelet rich plasm (PRP) into the scalp. But no, there is absolutely no evidence that either of these work to grow hair and applying it to your scalp will not get it inside of the scalp because the epidermis (a 1/2 mm thick tough element of the skin) protects the scalp largely from outside influences. So, although I wish you luck on your experiment which I hope to see results here on Reddit in the future, I am not optimistic about it.