Scholars have permitted Ruqya by means of the Qur'aan based on personal experience. That means if a person recites specific Qur'aanic Verses a specific number of times and is able to benefit from them for a given disease, he can prescribe the dhikr to someone else and use it for himself.
This is what doing Ruqya based on experience means. If you recite Verses of the Qur'aan, and then do Ruqya and see that the Ruqya benefits, you are allowed to continue on doing so. You can also prescribe the dhikr to others so that they may benefit.
Ruqya by means of the Qur'aan which is based on personal experience is something the scholars have permitted. The evidence for it being permitted is the following narration:
Narrated Abu Sa`id Al-Khudri:
While we were on one of our journeys, we dismounted at a place where a slave girl came and said, "The chief of this tribe has been stung by a scorpion and our men are not present; is there anybody among you who can treat him (by reciting something)?" Then one of our men went along with her though we did not think that he knew any such treatment. But he treated the chief by reciting something, and the sick man recovered whereupon he gave him thirty sheep and gave us milk to drink (as a reward). When he returned, we asked our friend, "Did you know how to treat with the recitation of something?" He said, "No, but I treated him only with the recitation of the Mother of the Book (i.e., Al-Fatiha)." We said, "Do not say anything (about it) till we reach or ask the Prophet (sallallaahu alayhi wa sallam) so when we reached Medina, we mentioned that to the Prophet (in order to know whether the sheep which we had taken were lawful to take or not). The Prophet (sallallaahu alayhi wa sallam) said, "How did he come to know that it (Al-Fatiha) could be used for treatment? Distribute your reward and assign for me one share thereof as well."
[Sahih al-Bukhaari Hadiith No. 5007]
Ibn Hajar said: It is apparent that he did not have prior knowledge of the Ruqya [he used] being legislatively stipulated. That is why his companions asked him did you know how to treat with the recitation of something?
Based on this if a person who does Ruqya has experienced that reciting a Qur'aanic Verse(s) a certain number of times brings about benefit, there is no harm in him using that and telling others about it so long as you do not begin to believe that doing so is an established Sunnah which one cannot increase over or decrease in.
Scholars have permitted Ruqya the benefit of which one has come to know and has been established by means of experience.
al-Imaam al-Qurtubi has reported from Yahyaa bin Abi Kathiir that the person who recites Suurah Yaa Siin at night will be happy until morning, and the person who recites the Suurah during the morning will be happy until the night.
Thus, when a person comes to know of a benefit from Ruqya of Qur'aanic Verses based on experience then there is nothing, legislatively speaking, which would prevent him from using it as Ruqya to benefit himself and others. There is no harm with such Ruqya.
As long as Ruqya does not contain shirk or anything else impermissible, you can use the Ruqya.