Looking for a gene in my raw genetic data. What are the possible causes for this?
Let's set things straight. The genomes of humans are highly similar and in general everyone shares the same genes. SNPs, or Single Nucleotide Polymorphisms, are single basepair positions in the genome in which there tend to be differences between people. This means, that instead of measuring the whole genome sequence for a person, which is very expensive and difficult, we can just examine a subset of the genome (the SNP positions) and capture most of the unique characteristics of that genome.

23andMe do exactly that. They measure a large set of SNPs (but not all of them), and thus give you some useful information about your unique DNA sequence. So you would need to look in the output given to you by 23andMe and see if they measure the SNP in question (rs35705950).

What do SNPs have to do with genes then? Well, if one of these SNPs occurs inside a gene, it could affect the gene, for example by producing a slightly different protein that could lead to some phenotype. So, studies link SNPs to different phenotypes such as disease or hair color. Usually the link is not one-to-one, but given as a probability.