I would get an infrared light 850nm they don't generate much heat and penetrate much deeper. A small cheap roundish security camera infrared light around $10 will do the job. Try to keep it around 5 minutes https://www.amazon.com/dp/B00ITKO9NW/ref=cm_sw_r_cp_apa_fabc_ZCCE3EWKSCT2W3A98K81

I have used them for the same purpose and they work good.

Do another 5 minutes in the area between testicles and anus