Using Kushta Rakshasa Taila for dandruff and eczema, especially around the groin, can help, but it does require a careful approach. You’re correct in observing that the taila (oil), being katu (pungent) and tikta (bitter), can elevate pitta dosha if not used correctly, potentially leading to issues like palitya (premature greying).
For treating dandruff, you could apply it in moderation. A small amount of oil massaged gently onto the scalp can help balance excess kapha and vata doshas responsible for dandruff. Mix the oil with a bit of coconut oil to help cool down any pitta aggravation. Leave it on for about 30 minutes before washing it off with a mild, herbal shampoo. Do this 1-2 times a week, depending on the severity, and observe how your scalp responds to prevent any increase in heat symptoms like itching or redness.
For eczema on groins, Ayurveda suggests starting with cleansers like neem-based or turmeric pastes to address underlying infection and inflammation. After a gentle cleansing, a light application of kushta rakshasa taila could be used; mix with cooling agents like sandalwood powder or aloe vera gel to prevent overheating and calm pitta dosha. This can be applied daily — but if any irritation occurs, cease usage immediately.
Prioritize hidration and diet. Consume cooling, mildly bitter foods and stay hydrated to balance internal pitta. If symptoms persist or worsen, consulting with a practicioner would provide more personalized insight and potentially explore other formulations or treatment modalitys to soothe and balance effectively.