I have read probably more books written by and or about exorcists than is good for me.
This of course has come up in interviews and so on, and by that I mean attacks on exorcists in general. The answer I would give as a result of all that reading is yes and no. I know of at least two exorcists that had to retire after debilitating attacks during or after a particularly rigorous exorcism. [from the books]
Others have reported problems from a demon they were later to exorcise, and of course there is always danger of attacks during the exorcism. From my understanding, mistakes made during a exorcism or before one can be dangerous. The priest has to be adequately predisposed ahead of time.
All of this being said, there are plenty of people needing this ministry and when the prayers begin it can be nothing more than foul language and spitting. I would say most of them are like that. Sometimes it takes years to liberate someone. The person receiving this ministry has to cooperate with the process too. They have to go to confession and live an upright lifestyle. No porn no occult practices etc.
So there is always the potential for bad things happening, but being properly disposed and experienced goes a long way, and then of course God’s will and purpose. So once again, the answer is yes and no.