A good flank and aerial enemies can give Pip a hard time that he will not use potions for allies instead for himself. Try use cauterize as well. Resilience also a good counter for his slow and chicken durations.
Always reload before using [Evil Mojo], as you only get a short amount of time to kill off everyone affected. It is also a good idea to save it until multiple allies are nearby, if at all possible.
If Evil Mojo is bringing you down, remember that Resilience is a thing. Oftentimes it can even be better than Blast Shields or Haven depending on the enemy's CCs.
Unlike certain champions, Pip's damage is the same from wherever you fire from or where you hit. Remember to keep distance and practice getting used to the arc of his attacks.
Pip struggles to hit enemies with high ground; it may even be harder than hitting Drogoz out of the air. Always keep the height advantage over him to force him to decide between AoE or a potential miss.