Ruido

In the last photos I took at iso 800 in RAW, it's a photo of a dance show in a dark theater I've always done but the last ones when editing are very noisy and when trying to make it smaller with the detail tool it's leaving the photo superficial. 

This is also happening with my friend on another camera and another photo occasion

By @Ivellize_Mafra

My guess is that the image is underexposed, and you have increased the exposure and/or lifted the shadows to compensate.

This will unavoidably lead to noise (especially in the shadows) in high ISO images.

Please post a screenshot of the entire LrC window with the image below open in Develop. (click on the Import step in the History panel).

Make sure that the History panel is visible and expanded on the left, and that the Histogram and Basic panel are visible and expanded on the right.

Do not attach the screenshot, use the Insert Photos button in the toolbar to embed it in your post.