Blown apex seal? Need help

[addmc]

Hi all,

New to the forum and to cars in general. This is my first car. 13B RE-EGI GSL SE

While assembling the distributor (was previously off because this car is a restoration), I set the timing incorrectly by about 90 degrees. When attempting to start the car, I heard a loud bang, almost like someone dropped a tool on the ground. Now I am scared that one of my apex seals might have been broken.

Here is what I have tried to confirm the integrity of the engine:

-Turning over manually to hear the compression. I hear 6 wooshes, but one of them sounds weak and not like the others.
-Trying to inspect the apex seals through the spark plug holes. Can see 2 of the 1st and 2nd rotor apex seals, but I haven't gotten a good picture of the 3rd seal. Can't really see anything through the spark plug holes, though.

I don't know where to get a rotary compression tester, and am worried of any type of damage to the engine. Can anyone maybe diagnose if my engine is toast or if I can fix the timing and try to start it.