I have thinning hair on the front of my head, i.e., all the hair on the front of my head is thinning and my scalp is visible; the same is true of a small part of the back of my head. Is it possible that I could do something Islamically prescribed or permissible, such as surgery and the like, to change its appearance, and what is your opinion on applying kohl to my head to conceal the baldness?

Would I have been deceiving my boss or manager at work, and would there be anything dubious about my salary, or am I taking my salary for my effort and my work, and does it have nothing to do with my hair?

Secondly: if I get married, and I do not tell my fiancée the truth about my hair or, for example, if I tell her but she has not seen my head, would my marriage be regarded as invalid?

Praise
be to Allah.

Firstly: 

In
the answer to question no. 194116 we stated that there
is nothing wrong with applying kohl to conceal baldness, and that is not
regarded as changing the creation of Allah, may He be exalted; rather it
comes under the heading of permissible adornments. 

You
do not have to tell your boss about it, because it does not have any impact
on your work; hence it does not have any impact on your salary either. 

Secondly: 

The
basic principle is that it is not permissible for the suitor to conceal any
defects that may have a negative impact on married life in the sense that
the wife would be put off by them, or they would prevent intimacy between
them, or would make him unable to fulfill his wife’s rights. 

Based
on that: 

If
the baldness is minimal, or it is something common and ordinary, then you do
not have to disclose it. 

But
if the baldness is complete and may be off-putting, or it would affect the
woman’s decision to marry, then in this case it is not permissible to
conceal it, because that is a kind of deception. 

There
is nothing wrong with you having hair transplant surgery; in sha Allah that
will be a means of correcting the defect. 

For
more information, please see the answer to questions no.
13215 and 47664.

And
Allah knows best.