Blitting an image in pygame immediately disappears after I release my mouse - python-3.x

Question

def options():
options = True
while options:
for event in pygame.event.get():
win.fill(WHITE)
win.blit(background, (0, 0))
... # Blitting text and switch buttons
options_x, options_y = pygame.mouse.get_pos()
if event.type == pygame.QUIT:
# Exit button
pygame.QUIT()
quit()
elif event.type == pygame.MOUSEBUTTONDOWN:
# Sound effect tuning
if 470 > options_x > 390 and 220 > options_y > 185:
# Checking if mouse click is on the ON SWITCH
mouse_click.play()
screen.blit(off_switch, (off_switch_x, off_switch_y))
pygame.mixer.stop()
# But doesn't stop sound from playing when I quit options section
# Music effect tuning
elif 470 > options_x > 390 and 300 > options_y > 260:
# Checking if mouse click is on the ON SWITCH
mouse_click.play()
screen.blit(off_switch, (off_switch_x, off_switch_y))
pygame.mixer.music.stop()
# Interactive BACK button
elif 90 > options_x > 42 and 75 > options_y > 25:
mouse_click.play()
options = False
pygame.display.update()
So this is a part of my HANGMAN game where I try to set up the OPTIONS section which allows you to configure the volume.
The problem is in the "Music" and "Sound" effect tuning.
Pressing on the ON SWITCH button for both "Music" and "Sound" will display the OFF SWITCH, but as soon as I release my mouse, they go back to their original state.
The music stops, but not the sound effects (mouse clicks, plop sounds, etc...).
I would like the image blitting to be saved, and the sounds effects to be stopped.
How can I fix this?

Answer 1

You undo the blit in every loop. At the top I see code which clears\resets everything.
win.fill(WHITE)
win.blit(background, (0, 0))
....
You blit the change inside the event handler:
screen.blit(off_switch, (off_switch_x, off_switch_y))
The event switch blit will be cleared at the next event loop (probably mouse move).
Think of the game as a series of states. The code at the top of the loop should draw the current state of the game.
for event in pygame.event.get():
win.fill(WHITE)
win.blit(background, (0, 0))
if SwitchIsOn:
screen.blit(on_switch, (on_switch_x, on_switch_y))
else:
screen.blit(off_switch, (off_switch_x, off_switch_y))
....
The event handler should be used to change the game state.
if 470 > options_x > 390 and 220 > options_y > 185:
# Checking if mouse click is on the ON SWITCH
mouse_click.play()
SwitchIsOn = not SwitchIsOn # reverse switch position
This will prevent your event changes from being cleared.