I got my photos from my disposable cameras and I’m missing about 18 of them out of 52. I was just wondering if I could get the rest of them back.
You would have to contact the company you used to develop the photos. this is assuming that your disposable cameras are film.
In the past (way way way past) I've had situations where some of the photos were so under exposed that they were excluded in the print photo delivery, possibly this is the cause.
Contact the development company and see.
You would need to examine the negatives or talk with the company who developed/printed the film to be sure, but the most likely explanation is that these frames were simply underexposed too much and weren't worth printing. They would have been dark/black with nothing discernible in the scene. Film works better in good light, and especially when the camera uses a cheap lens. Even if the camera has a flash, this is very weak and won't light up anything that's more than a few feet from the camera.
While it's tempting to use these cameras indoors at events and parties and so on, they are probably better suited to outdoor daytime activities in sunlight.
All the "disposable"* cameras I've seen use 35mm film cartridges. These generally comes in nominal sizes of 24 or 36 exposures. Often in practice you get slightly more than the nominal amount but unless this camera or it's film were something very unusual, 52 is way beyond what you can expect.
Thus my conclusion is that your camera had a problem with the film advance mechanism that caused it to either continue taking photos after the film had run out, or caused it to take multiple exposures on the same frame of film.
If you look at the negatives (Any decent processing lab should include the negatives) you might find a frame or two of messed-up photos that were not printed, but you aren't going to find 18 of them. There simply isn't enough space on the film.
* Most of them can actually be reloaded, the catch is that the process to reload the film has to be done in the dark.