You said you developed your first roll and your local lab developed and scan the negatives ? I am assuming you did the developing of the film and the local lab did the scanning. Having said that.
if you have one good image or more in the same roll, then it is to be believed that the developing (processing) was correct, and the bad images are a product of bad exposure combined with scanning settings that are not optimal to the bad images. The lab may have done a batch scan without paying detailed attention to the bad images. Although somewhat they can be improved, they will be far from perfect due to incorrect exposure settings.

Give it a second try paying more close attention to exposure and try again with exact same procedure you did before. If you know for a fact that your exposure is correct, then you can move on to the next variable.

Regards,