Do you mean the edit pins to select one of the applied brushes? What happens if you press H?
If not, please post a screen-shot.
Nothing happens when H is pressed. Yes wen I select the adjustment brush
pin, Mark the face and increase the exposure, that's wen the black spots
Turn "Auto Mask" OFF in the brush tool settings
Sounds like you may have the Mask overlay turned on with colour set to Grey-Black.
Press the O key to switch Mask Overlay on/off and Shift -O to change colour of the overlay (Grey/Red/Green or White)
(there is also a checkbox to show it's status on the toolbar.
Bob Somrak has the answer- Turn "Auto Mask" OFF in the brush tool settings.
To explain- When "Auto Mask" is ticked to turn on, the brush tool reads only the one pixel that is immediately under the centre + of the brush circle. Then the brush only changes pixels of similar TONE. In this way the brush can be used to selectively brush along edges where the tones change markedly.
On a very detailed part of the image with many different tones the "Auto Mask" changes some, but not all, of the pixels you paint, hence the spotty dots mentioned by the OP.
With "Auto Mask" turned on, as you brush, each time you click the left mouse button you are picking up a new tone to continue selectively brushing.
Thank you so much. Turned the auto mask off & it's fine now.