All of the answers given so far are super and so I will be repeating a lot of what has been said already.
A hair becomes 'ingrown' because the follicle (which moulds and shapes the body of the hair or hair shaft) has become distorted via methods of removal otherwise is naturally (genetically) curved/spiral in shape. Unfortunately whatever the 'cause' or 'reason' - the follicle cannot ever be 'straightened out'.
'Ingrown Hairs' must be watched carefully (hairs can, in some instances, grow down and inwards reaching the subcutaneous and muscle tissue - very painful, requiring incision, leaving scarring)
Tend Skin and Ingrow Go are great products. These products rapidly dehydrate the superficial layers of skin encouraging new fresh cells (lower down) 'push up' the flaky dead skin cells that are cocooning the shaft of the troublesome hair. Use of these products should be contained to the area and preferably applied with a cotton bud for precision. Re-apply as often as the product recommends and exfoliate (again with precision) before each re-application.
The only permanent method (I can suggest) that could attempt to control ingrown hair 'outbreaks' is light-based hair removal therapies who's aim is to destroy the follicle and stunt hair re-growth. Of course this remedy has to be considered very carefully because it is not able to 'selectively' destroy ingrown hairs whilst allowing 'okay' follicles to continue producing hairs ... In other words Laser, LHE and IPL etc will permanently reduce ALL the hair growth in the area of application
I hope this helps and doesn't confuse
PS. To avoid creating or exacerbating 'ingrown hairs' you should always visit an experienced professional for epilation. Incorrect plucking, threading and waxing (incorrect direction of removal) is a major cause of ingrown hairs however ROTARY EPILATORS ARE THE BIGGEST CREATORS OF INGROWN HAIRS - IF YOU HAVE AN EPILATOR - BIN IT ... NOW!!!
Exfoliating 2-3 times a week can help, and you can also buy creams to apply that can discourage ingrown hairs. Sometimes people are just prone to ingrown hairs. If you wax your hair the hair gets weaker and so can get caught under the skin as it is someimes not thick/strong enough to break through any dead skin cells etc that are on the skin. Hope that helps x